United States · Detailed regional profile

Napa Valley

A small California AVA known especially for Cabernet Sauvignon, with cooler conditions in the south and warmer sites farther north.

Summers are dry and warm, while marine air reaches parts of the valley. Heat, water stress, and harvest timing can all vary by site.

Climate comparisons use the 1991–2020 combined regional record · updated through Aug 20, 2026.

Autumn vineyard rows in Napa Valley, California — Vanessa Sezini / Pexels

Current conditions

Observations through Aug 31, 2026 · 00:30 UTC

Temperature23.7°C

Dew Point12.1°C

Relative Humidity50%

24h Rainfall0.0 mmmodeled IFS total through Aug 29

NWS station average · 2 stations

Temperature, dew point, humidity, and wind are averaged using the same locations and weights as the historical record. The current temperature uses 100% of the configured regional weight.

KAPC — Napa, Napa County Airport · 55% regional weight
KSTS — Santa Rosa, Santa Rosa Sonoma County Airport · 45% regional weight

NOAA National Weather Service observations. Station readings are point measurements and may not represent every vineyard elevation or exposure.

Vintage explorer

Compare this vintage →

Moderately cooler and significantly wetter than normal.

Mean temperature17.4°C

Temperature anomaly-1.0°Cvs 1991-2020

Growing degree days1842base 10°C

Hot days12≥ 35°C

What stood out in 2010

Cool weather can slow ripening and help grapes retain acidity. Frost exposure can vary sharply from one site to the next.

Cooler growing season · High confidence

Mean growing-season temperature was -1.0°C versus the 1991–2020 baseline.

Cool weather can slow ripening and help grapes retain acidity.

Spring frost recorded · Low confidence

The regional record had 1 spring day(s) at or below 0°C.

Frost exposure can vary sharply from one site to the next.

How unusual was 2010?

The ranking compares vintages that meet the data-coverage threshold and use the same source, regional rules, and 1991-2020 baseline.

Growing-season temperature

2nd coolest of 35 vintages Cooler than 32 of 34 other vintages 17.4°C

Growing-season rainfall

6th wettest of 35 vintages Wetter than 29 of 34 other vintages 290.7 mm

Heat accumulation

2nd lowest of 35 vintages Lower than 33 of 34 other vintages 1842 GDD

Hot days

16th fewest of 35 vintages Fewer than 18 of 34 other vintages 12 days

2010 month by month

Compared with 1991–2020

Follow heat accumulation, rainfall, frost exposure, and the region’s growing and harvest windows in calendar order.

Frost watch Growing season Harvest window

Mar ’10 1–31

Frost watchGrowing season

Heat accumulation

2010 54 GDD

Typical 83 GDD

Rainfall

2010 77.8 mm

Typical 111.5 mm

2010 freezing days
1

Typical
0.2

Heat accumulation ran behind the typical month.
Apr ’10 1–30

Frost watchGrowing season

Heat accumulation

2010 68 GDD

Typical 131 GDD

Rainfall

2010 112.8 mm

Typical 48.4 mm

2010 freezing days
0

Typical
0.0

Heat accumulation ran behind the typical month.
May ’10 1–31

Frost watchGrowing season

Heat accumulation

2010 143 GDD

Typical 226 GDD

Rainfall

2010 42.1 mm

Typical 29.5 mm

2010 freezing days
0

Typical
0.0

Heat accumulation ran behind the typical month.
Jun ’10 1–30

Growing season

Heat accumulation

2010 309 GDD

Typical 315 GDD

Rainfall

2010 0.2 mm

Typical 7.4 mm

Close to the typical monthly pattern.
Jul ’10 1–31

Growing season

Heat accumulation

2010 328 GDD

Typical 374 GDD

Rainfall

2010 0.0 mm

Typical 0.3 mm

Close to the typical monthly pattern.
Aug ’10 1–31

Growing seasonHarvest window

Heat accumulation

2010 311 GDD

Typical 372 GDD

Rainfall

2010 0.3 mm

Typical 1.1 mm

Close to the typical monthly pattern.
Sep ’10 1–30

Growing seasonHarvest window

Heat accumulation

2010 336 GDD

Typical 330 GDD

Rainfall

2010 1.4 mm

Typical 2.8 mm

Close to the typical monthly pattern.
Oct ’10 1–31

Growing seasonHarvest window

Heat accumulation

2010 216 GDD

Typical 232 GDD

Rainfall

2010 92.7 mm

Typical 37.0 mm

Wetter than the typical month.
Nov ’10 1–15

Growing seasonHarvest window

Heat accumulation

2010 76 GDD

Typical 55 GDD

Rainfall

2010 23.9 mm

Typical 30.6 mm

Heat accumulation ran ahead of the typical month.

View milestone calendar data as a table

Month	2010 GDD	Typical GDD	2010 rainfall	Typical rainfall	2010 freezing days	Typical freezing days
March 2010	54 GDD	83 GDD	77.8 mm	111.5 mm	1	0.2
April 2010	68 GDD	131 GDD	112.8 mm	48.4 mm	0	0.0
May 2010	143 GDD	226 GDD	42.1 mm	29.5 mm	0	0.0
June 2010	309 GDD	315 GDD	0.2 mm	7.4 mm	Outside frost window	Outside frost window
July 2010	328 GDD	374 GDD	0.0 mm	0.3 mm	Outside frost window	Outside frost window
August 2010	311 GDD	372 GDD	0.3 mm	1.1 mm	Outside frost window	Outside frost window
September 2010	336 GDD	330 GDD	1.4 mm	2.8 mm	Outside frost window	Outside frost window
October 2010	216 GDD	232 GDD	92.7 mm	37.0 mm	Outside frost window	Outside frost window
November 2010	76 GDD	55 GDD	23.9 mm	30.6 mm	Outside frost window	Outside frost window

Calendar data and method

Monthly values are weighted across every configured regional sample using stored Google ARCO ERA5 daily reanalysis. “Typical” is the mean monthly total across 30 baseline seasons. GDD is counted only inside the configured growing window; freezing days are counted only inside the frost-watch window; rainfall covers every displayed calendar day.

Selected-vintage coverage is 100%. Source rows were last retrieved Aug 20, 2026.

Replay the 2010 growing season

246 daily regional observations

Move through the season to follow temperature, rainfall, accumulated heat, and recorded weather events day by day.

Replay data and method

Daily values are weighted across every configured regional sample using stored Google ARCO ERA5 reanalysis. Coverage is 100%. Source rows were last retrieved Aug 20, 2026.

Closest weather matches

These years had the most similar growing-season and harvest weather.

Closest match
1998

Most alike in Growing-season mean temperature and Growing degree days.

Growing-season mean temperature
the same: 0.0°C
Growing degree days
higher: 5 GDD

Largest difference: Spring frost exposure — fewer frost-exposure days
View 1998 →
Second closest
1999

Most alike in Spring frost exposure and Hot-day count.

Spring frost exposure
the same: 0 days
Hot-day count
fewer hot days: 2 days

Largest difference: Growing-season precipitation — less rain
View 1999 →
Third closest
1994

Most alike in Growing degree days and Growing-season precipitation.

Growing degree days
higher: 103 GDD
Growing-season precipitation
less rain: 49.3 mm

Largest difference: Spring frost exposure — fewer frost-exposure days
View 1994 →

How similar years are calculated

Method analog-v1-2026-07 standardizes six weather measures across 34 complete ARCO ERA5 comparison years, then measures the distance between them. The calculation runs when the page is requested.

Measures used: Growing-season mean temperature (20%); Growing degree days (15%); Hot-day count (15%); Growing-season precipitation (20%); Harvest precipitation (20%); Spring frost exposure (10%).

Calculated distances: 1998 0.805; 1999 0.854; 1994 0.957.

Growing-season temperature anomalyCompared with 1991-2020

Growing-season rainfall anomaly

View historical chart data as a table

Year	Temperature anomaly	Rainfall anomaly	Hot days
1991	-0.6°C	+13 mm	10
1992	+0.7°C	-19 mm	9
1993	+0.1°C	+14 mm	10
1994	-0.6°C	+33 mm	7
1995	-0.4°C	+21 mm	16
1996	+0.2°C	+11 mm	23
1997	+0.8°C	-27 mm	10
1998	-1.0°C	+87 mm	16
1999	-0.6°C	-7 mm	10
2000	-0.2°C	-2 mm	13
2001	+0.6°C	-65 mm	17
2002	-0.2°C	-59 mm	16
2003	-0.1°C	+57 mm	17
2004	+0.3°C	-28 mm	7
2005	-0.5°C	+111 mm	10
2006	-0.2°C	+136 mm	16
2007	-0.1°C	-71 mm	11
2008	+0.1°C	-93 mm	18
2009	-0.2°C	-4 mm	17
2010	-1.0°C	+82 mm	12
2011	-1.1°C	+193 mm	3
2012	-0.5°C	+50 mm	9
2013	+0.3°C	-125 mm	13
2014	+0.8°C	-64 mm	6
2015	+0.7°C	-101 mm	17
2016	+0.3°C	+14 mm	14
2017	+0.8°C	+6 mm	27
2018	+0.2°C	-30 mm	7
2019	+0.4°C	-31 mm	13
2020	+0.9°C	-104 mm	23
2021	+0.3°C	+90 mm	12
2022	+0.5°C	-55 mm	18
2023	-0.6°C	-29 mm	10
2024	+0.8°C	-65 mm	28
2025	-0.0°C	-32 mm	7
2026	+0.5°C	-88 mm	7

winter

9.0°C

-0.5°C vs baseline

481 mm rain · +20 mm

spring

12.6°C

-2.0°C vs baseline

232 mm rain · +43 mm

summer

20.3°C

-1.2°C vs baseline

0 mm rain · -8 mm

harvest

18.8°C

-0.4°C vs baseline

118 mm rain · +47 mm

Weather events

Periods that crossed one of the published regional thresholds, shown in date order.

Mar 13, 2010
Spring frost exposure
Minimum temperature
-0.1°C
Duration
1 day
Severe-freeze days
0 days
The regional model recorded freezing temperatures during spring.
May 29–Sep 18, 2010
Dry spell
Duration
113 days
Total rain
0.6 mm
Daily cutoff
1.0 mm/day
Jun 27–28, 2010
Heat episode
Peak temperature
35.7°C
Duration
2 days
Heat accumulation
31 GDD
Aug 23–25, 2010
Heat episode
Peak temperature
39.5°C
Duration
3 days
Heat accumulation
51 GDD
Sep 1–2, 2010
Heat episode
Peak temperature
35.9°C
Duration
2 days
Heat accumulation
31 GDD
Sep 20–Oct 16, 2010
Dry spell
Duration
27 days
Total rain
0.3 mm
Daily cutoff
1.0 mm/day
Sep 26–29, 2010
Heat episode
Peak temperature
37.7°C
Duration
4 days
Heat accumulation
62 GDD
Oct 22–26, 2010
Concentrated harvest rain
Total rain
75.7 mm
Highest 3-day total
71.5 mm
Trigger threshold
20.0 mm
A large share of the season's rain fell during the harvest period.
Nov 5–9, 2010
Concentrated harvest rain
Total rain
21.4 mm
Highest 3-day total
21.0 mm
Trigger threshold
20.0 mm
A large share of the season's rain fell during the harvest period.

How events are detected

Weather & Vines combined regional series; method event-timeline-v2-2026-07, rules napa-v2-2026-07. Source last updated Aug 1, 2026, calculated Aug 29, 2026. Each configured point must have at least 95.0% coverage.

1991–present

Climate change

Measured regional trends are shown separately from model projections. The observed record ends at the latest complete growing season shared by every published region.

Compare regions

Observed record

Historical trends, 1991–2025

Growing degree days changed +42.2 GDD per decade. The 95% interval is +10.8 to +73.7 GDD per decade, based on 35 eligible vintages.

How it is measured: Across the March 15–November 15 growing season, each day's mean temperature above 10°C adds to the total; cooler days add zero.

Growing degree days · annual change from the 1991–2020 average1991–2025

Scroll horizontally to inspect the full timeline.

View annual growing degree days data

Vintage	Growing degree days	Change from 1991–2020
1991	1962 GDD	-124 GDD
1992	2259 GDD	+173 GDD
1993	2089 GDD	+3 GDD
1994	1945 GDD	-141 GDD
1995	1988 GDD	-98 GDD
1996	2140 GDD	+54 GDD
1997	2272 GDD	+186 GDD
1998	1848 GDD	-238 GDD
1999	1942 GDD	-144 GDD
2000	2044 GDD	-42 GDD
2001	2231 GDD	+145 GDD
2002	2034 GDD	-52 GDD
2003	2080 GDD	-6 GDD
2004	2144 GDD	+58 GDD
2005	1952 GDD	-134 GDD
2006	2037 GDD	-49 GDD
2007	2064 GDD	-22 GDD
2008	2116 GDD	+30 GDD
2009	2036 GDD	-50 GDD
2010	1842 GDD	-244 GDD
2011	1824 GDD	-262 GDD
2012	1976 GDD	-110 GDD
2013	2141 GDD	+55 GDD
2014	2278 GDD	+192 GDD
2015	2252 GDD	+166 GDD
2016	2139 GDD	+53 GDD
2017	2281 GDD	+195 GDD
2018	2156 GDD	+70 GDD
2019	2184 GDD	+98 GDD
2020	2325 GDD	+239 GDD
2021	2151 GDD	+65 GDD
2022	2212 GDD	+126 GDD
2023	1966 GDD	-120 GDD
2024	2292 GDD	+206 GDD
2025	2077 GDD	-9 GDD

Growing-season mean temperature: +0.17 °C per decade 95% interval +0.04 to +0.30
Growing degree days: +42.21 GDD per decade 95% interval +10.75 to +73.68
Growing-season precipitation: -15.39 mm per decade 95% interval -26.01 to -4.76
Hot days: +1.02 days per decade 95% interval -0.30 to +2.34
Spring frost days: +0.03 days per decade 95% interval -0.07 to +0.14
Longest dry spell: +7.97 days per decade 95% interval -1.34 to +17.29

Last Updated August 20, 2026

Model ensemble

Projected climate through 2075

Temperature changes are relative to each model’s 1991–2020 baseline. The table combines all three pathways, weighted 70% to SSP2-4.5 and 15% each to SSP1-2.6 and SSP3-7.0.

Scroll horizontally to compare all columns.

Period	Weighted median	Weighted central 80%	Models per pathway
2021-2040	+0.9°C	+0.5 to +1.3°C	25
2041-2060	+1.3°C	+1.0 to +2.1°C	25
2061-2075	+1.8°C	+1.4 to +2.7°C	25

How pathways are combined

For each period and percentile, Weather & Vines takes 70% of the SSP2-4.5 value, 15% of the SSP1-2.6 value, and 15% of the SSP3-7.0 value. Each pathway contains the same 25 models. The weights are an editorial view of the current trajectory, not scenario probabilities.

Last Updated June 29, 2025

Compare projection measures across regions

Typical year · 1991–2020

When to visit

This calendar describes typical regional weather under the selected climate baseline. It is not a forecast for a future trip, and it does not account for crowds, lodging, events, or vineyard access.

Deterministic IFS forecast

Next ten days

Detailed forecast outlook

ECMWF IFS 0.25° via Herbie · model run Aug 30, 2026 at 00:00 UTC · retrieved Aug 30, 2026 at 08:22 UTC

Scroll horizontally to see all forecast dates.

Date	SunAug 30	MonAug 31	TueSep 1	WedSep 2	ThuSep 3	FriSep 4	SatSep 5	SunSep 6	MonSep 7	TueSep 8
High	29°C	23°C	20°C	21°C	24°C	26°C	26°C	29°C	26°C	26°C
Low	12°C	12°C	12°C	12°C	12°C	14°C	12°C	12°C	17°C	19°C
Rain	0.0 mm	0.0 mm	0.1 mm	0.0 mm	0.0 mm	0.0 mm	0.0 mm	0.0 mm	0.5 mm	0.8 mm

Across the typical year: Late July has the warmest median afternoon high (30.7°C); Late December has the coolest (13.0°C). Wet days are most frequent in Late February (42%) and least frequent in Early July (0%). Ties are resolved by calendar order.

Typical afternoon highs and overnight lowsMedians and middle 50% of daily readings

Afternoon highOvernight lowMiddle 50%

Scroll horizontally to inspect all 24 half-month periods.

How often a day is wetShare of days with at least 1 mm of rain

Scroll horizontally to inspect all 24 half-month periods.

View all 24 periods as a table

Scroll horizontally to view all columns.

Napa Valley typical weather by half-month, 1991–2020
Period	Afternoon high, median (middle 50%)	Overnight low, median (middle 50%)	Wet-day frequency	Period rain, median (middle 50%)
Jan 1–15	13.3°C (11.4–15.3°C)	4.0°C (2.1–6.2°C)	36%	49.2 mm (8.9–99.9 mm)
Jan 16–31	14.0°C (12.4–16.6°C)	4.5°C (2.6–6.8°C)	40%	48.6 mm (18.5–130.2 mm)
Feb 1–15	15.4°C (13.6–18.3°C)	5.2°C (3.2–7.5°C)	35%	55.3 mm (15.1–107.5 mm)
Feb 16–29	15.1°C (12.6–18.8°C)	5.4°C (3.3–7.1°C)	42%	70.1 mm (26.7–130.9 mm)
Mar 1–15	17.4°C (14.3–20.7°C)	6.0°C (4.0–8.1°C)	36%	53.1 mm (13.9–79.5 mm)
Mar 16–31	18.4°C (15.5–22.2°C)	6.8°C (4.8–8.5°C)	33%	24.2 mm (11.6–71.7 mm)
Apr 1–15	19.4°C (16.4–22.4°C)	6.7°C (4.9–8.5°C)	27%	24.8 mm (10.5–55.7 mm)
Apr 16–30	21.9°C (19.0–26.0°C)	8.3°C (6.5–10.0°C)	18%	13.0 mm (6.1–23.4 mm)
May 1–15	23.8°C (20.4–26.8°C)	9.3°C (7.8–10.9°C)	14%	4.2 mm (0.7–21.7 mm)
May 16–31	25.0°C (21.9–28.5°C)	10.3°C (9.0–11.9°C)	13%	3.1 mm (0.4–25.7 mm)
Jun 1–15	27.5°C (24.7–30.7°C)	11.7°C (10.3–13.3°C)	6%	0.7 mm (0.0–3.2 mm)
Jun 16–30	29.5°C (27.0–32.4°C)	12.5°C (11.2–14.1°C)	3%	0.0 mm (0.0–0.8 mm)
Jul 1–15	30.3°C (28.4–32.6°C)	13.0°C (12.0–14.3°C)	0%	0.0 mm (0.0–0.0 mm)
Jul 16–31	30.7°C (28.2–32.7°C)	13.5°C (12.3–14.7°C)	0%	0.0 mm (0.0–0.1 mm)
Aug 1–15	30.5°C (28.1–33.1°C)	13.2°C (12.2–14.6°C)	0%	0.0 mm (0.0–0.1 mm)
Aug 16–31	30.0°C (28.1–32.8°C)	13.1°C (12.1–14.2°C)	1%	0.0 mm (0.0–0.1 mm)
Sep 1–15	29.5°C (27.3–32.5°C)	12.5°C (11.4–14.1°C)	2%	0.0 mm (0.0–0.3 mm)
Sep 16–30	29.0°C (26.2–31.8°C)	12.1°C (10.9–13.4°C)	4%	0.2 mm (0.0–1.6 mm)
Oct 1–15	26.2°C (23.1–29.3°C)	10.7°C (9.1–12.3°C)	9%	2.2 mm (0.0–17.9 mm)
Oct 16–31	23.4°C (20.6–26.6°C)	9.6°C (7.9–11.0°C)	16%	11.6 mm (0.4–34.3 mm)
Nov 1–15	19.2°C (16.6–22.6°C)	7.4°C (5.5–9.2°C)	21%	20.6 mm (6.5–46.7 mm)
Nov 16–30	16.2°C (14.1–18.3°C)	5.5°C (3.7–7.8°C)	30%	29.7 mm (20.8–58.0 mm)
Dec 1–15	14.1°C (12.7–15.9°C)	4.4°C (2.4–7.5°C)	42%	68.3 mm (22.1–123.0 mm)
Dec 16–31	13.0°C (11.4–15.1°C)	3.5°C (1.8–5.5°C)	35%	53.8 mm (9.9–127.5 mm)

Each year contributes to temperature or rain separately when at least 90% of that period’s days are present. A value is shown only when at least 80% of the baseline years qualify. February 29 is included in late February.

Historical climatology Last Updated August 20, 2026

Season to date

Growing season heat and rainfall

Mar 15–Aug 29, 2026

Growing degree days1455.9base 10°C

Growing-season rainfall120.8 mmweighted regional total

Cumulative growing degree daysBase 10°C

2026 season1991–2020 average

Cumulative growing-season rainfallRegional weighted mean

2026 season1991–2020 average

View growing-season accumulation data

Date	Season GDD	1991–2020 average GDD	Season rainfall	1991–2020 average rainfall
2026-03-15	8.8	3.2	0.0 mm	4.1 mm
2026-03-16	19.1	6.6	0.0 mm	7.4 mm
2026-03-17	29.9	10.1	0.0 mm	9.8 mm
2026-03-18	40.7	13.6	0.0 mm	11.3 mm
2026-03-19	51.9	17.0	0.0 mm	13.5 mm
2026-03-20	63.9	20.1	0.0 mm	18.1 mm
2026-03-21	75.0	23.0	0.0 mm	21.1 mm
2026-03-22	83.6	25.6	0.0 mm	25.8 mm
2026-03-23	91.5	28.0	0.0 mm	30.4 mm
2026-03-24	99.5	30.1	0.0 mm	35.6 mm
2026-03-25	106.4	32.2	0.0 mm	39.8 mm
2026-03-26	113.4	34.4	0.0 mm	42.2 mm
2026-03-27	121.9	37.0	0.0 mm	44.7 mm
2026-03-28	129.9	40.2	0.0 mm	46.4 mm
2026-03-29	139.4	43.8	0.0 mm	48.1 mm
2026-03-30	147.5	47.6	0.0 mm	48.8 mm
2026-03-31	152.5	51.4	6.2 mm	51.7 mm
2026-04-01	154.9	55.2	9.9 mm	54.7 mm
2026-04-02	156.0	59.1	12.7 mm	56.0 mm
2026-04-03	160.7	62.4	12.7 mm	57.5 mm
2026-04-04	166.9	65.4	12.7 mm	60.3 mm
2026-04-05	174.4	68.3	12.7 mm	62.2 mm
2026-04-06	180.7	71.4	12.7 mm	64.6 mm
2026-04-07	186.2	74.6	12.7 mm	67.9 mm
2026-04-08	193.1	77.4	12.8 mm	70.3 mm
2026-04-09	199.4	80.4	12.9 mm	71.5 mm
2026-04-10	203.9	84.1	24.5 mm	72.7 mm
2026-04-11	205.2	87.7	41.3 mm	76.1 mm
2026-04-12	205.5	91.5	55.3 mm	80.8 mm
2026-04-13	206.4	95.3	57.0 mm	83.1 mm
2026-04-14	208.0	99.1	57.0 mm	83.6 mm
2026-04-15	209.9	102.3	57.0 mm	84.4 mm
2026-04-16	213.0	106.1	57.0 mm	86.2 mm
2026-04-17	218.0	110.4	57.0 mm	88.3 mm
2026-04-18	222.7	114.7	57.0 mm	89.2 mm
2026-04-19	227.6	119.4	57.0 mm	89.9 mm
2026-04-20	229.9	124.4	67.3 mm	91.2 mm
2026-04-21	231.4	129.4	91.2 mm	91.9 mm
2026-04-22	232.8	134.8	99.6 mm	93.1 mm
2026-04-23	235.8	140.1	99.6 mm	94.4 mm
2026-04-24	239.5	145.6	99.6 mm	95.5 mm
2026-04-25	241.2	151.0	99.6 mm	97.1 mm
2026-04-26	242.6	156.8	99.7 mm	97.6 mm
2026-04-27	244.8	162.8	100.1 mm	98.2 mm
2026-04-28	248.1	168.9	100.1 mm	99.2 mm
2026-04-29	253.6	175.4	100.1 mm	99.9 mm
2026-04-30	260.4	182.2	100.1 mm	100.1 mm
2026-05-01	267.3	189.2	100.1 mm	101.6 mm
2026-05-02	272.2	196.1	100.1 mm	102.6 mm
2026-05-03	276.0	202.6	100.1 mm	103.9 mm
2026-05-04	278.1	208.9	102.1 mm	104.7 mm
2026-05-05	281.2	215.1	110.0 mm	105.8 mm
2026-05-06	287.4	221.3	110.0 mm	106.3 mm
2026-05-07	294.4	228.0	110.0 mm	107.5 mm
2026-05-08	301.7	234.9	110.0 mm	108.4 mm
2026-05-09	310.6	241.5	110.0 mm	109.2 mm
2026-05-10	319.3	248.3	110.0 mm	109.7 mm
2026-05-11	329.9	255.1	110.0 mm	110.0 mm
2026-05-12	338.8	261.8	110.0 mm	110.9 mm
2026-05-13	346.7	268.4	110.0 mm	111.4 mm
2026-05-14	355.4	275.3	110.0 mm	112.0 mm
2026-05-15	365.2	282.6	110.0 mm	114.3 mm
2026-05-16	373.8	289.8	110.0 mm	116.4 mm
2026-05-17	380.9	297.1	110.0 mm	117.8 mm
2026-05-18	390.6	304.5	110.0 mm	120.3 mm
2026-05-19	401.4	311.8	110.0 mm	121.6 mm
2026-05-20	412.4	319.0	110.0 mm	122.2 mm
2026-05-21	423.8	326.6	110.0 mm	123.4 mm
2026-05-22	432.5	334.4	110.0 mm	123.6 mm
2026-05-23	439.3	342.6	110.0 mm	124.0 mm
2026-05-24	445.5	350.5	110.0 mm	124.6 mm
2026-05-25	449.8	358.2	110.0 mm	125.3 mm
2026-05-26	454.4	365.5	110.7 mm	125.9 mm
2026-05-27	458.6	373.2	112.6 mm	126.9 mm
2026-05-28	463.6	381.3	119.4 mm	127.9 mm
2026-05-29	469.4	389.9	120.2 mm	128.8 mm
2026-05-30	476.1	398.6	120.2 mm	129.1 mm
2026-05-31	485.2	408.0	120.2 mm	129.6 mm
2026-06-01	496.1	417.8	120.2 mm	129.8 mm
2026-06-02	506.3	427.4	120.2 mm	129.9 mm
2026-06-03	517.5	436.9	120.2 mm	130.2 mm
2026-06-04	529.5	446.2	120.2 mm	131.9 mm
2026-06-05	542.5	455.3	120.2 mm	132.3 mm
2026-06-06	552.8	464.1	120.2 mm	132.3 mm
2026-06-07	561.3	473.1	120.2 mm	132.4 mm
2026-06-08	569.7	482.7	120.4 mm	132.9 mm
2026-06-09	579.6	492.7	120.4 mm	133.0 mm
2026-06-10	594.5	502.6	120.4 mm	133.1 mm
2026-06-11	612.8	512.7	120.4 mm	133.2 mm
2026-06-12	627.8	523.0	120.4 mm	133.4 mm
2026-06-13	641.0	533.6	120.4 mm	133.4 mm
2026-06-14	652.6	544.5	120.4 mm	133.5 mm
2026-06-15	663.8	554.9	120.4 mm	133.8 mm
2026-06-16	674.0	565.4	120.4 mm	134.3 mm
2026-06-17	683.6	576.2	120.4 mm	134.5 mm
2026-06-18	691.7	587.2	120.4 mm	134.6 mm
2026-06-19	699.3	598.3	120.4 mm	134.6 mm
2026-06-20	707.7	609.6	120.4 mm	134.6 mm
2026-06-21	716.9	620.8	120.4 mm	134.6 mm
2026-06-22	726.3	632.2	120.4 mm	134.6 mm
2026-06-23	735.4	643.4	120.4 mm	134.6 mm
2026-06-24	744.1	654.5	120.4 mm	134.7 mm
2026-06-25	753.2	665.7	120.4 mm	135.1 mm
2026-06-26	762.5	676.9	120.5 mm	135.2 mm
2026-06-27	771.4	688.3	120.5 mm	135.3 mm
2026-06-28	780.9	699.7	120.5 mm	136.3 mm
2026-06-29	791.4	711.2	120.5 mm	136.9 mm
2026-06-30	801.7	723.3	120.5 mm	137.1 mm
2026-07-01	810.9	735.4	120.5 mm	137.1 mm
2026-07-02	819.8	747.3	120.5 mm	137.1 mm
2026-07-03	829.7	759.0	120.5 mm	137.1 mm
2026-07-04	840.3	771.0	120.5 mm	137.1 mm
2026-07-05	849.7	782.7	120.5 mm	137.1 mm
2026-07-06	858.4	794.4	120.5 mm	137.1 mm
2026-07-07	866.8	806.1	120.5 mm	137.1 mm
2026-07-08	876.0	818.2	120.5 mm	137.1 mm
2026-07-09	887.9	830.2	120.5 mm	137.1 mm
2026-07-10	898.9	842.0	120.5 mm	137.2 mm
2026-07-11	909.7	853.6	120.5 mm	137.2 mm
2026-07-12	923.2	865.4	120.5 mm	137.2 mm
2026-07-13	938.2	877.9	120.5 mm	137.2 mm
2026-07-14	954.6	890.3	120.5 mm	137.2 mm
2026-07-15	971.6	902.6	120.5 mm	137.2 mm
2026-07-16	985.3	914.5	120.5 mm	137.2 mm
2026-07-17	995.9	926.4	120.5 mm	137.2 mm
2026-07-18	1006.5	938.4	120.5 mm	137.3 mm
2026-07-19	1017.3	950.5	120.5 mm	137.3 mm
2026-07-20	1028.7	962.4	120.6 mm	137.3 mm
2026-07-21	1043.9	974.2	120.6 mm	137.3 mm
2026-07-22	1056.0	986.4	120.6 mm	137.3 mm
2026-07-23	1067.4	998.8	120.6 mm	137.3 mm
2026-07-24	1079.6	1011.1	120.6 mm	137.3 mm
2026-07-25	1091.9	1023.5	120.6 mm	137.3 mm
2026-07-26	1104.2	1036.1	120.6 mm	137.3 mm
2026-07-27	1115.9	1048.7	120.6 mm	137.3 mm
2026-07-28	1128.4	1061.1	120.6 mm	137.3 mm
2026-07-29	1141.5	1073.1	120.6 mm	137.3 mm
2026-07-30	1154.5	1085.3	120.6 mm	137.3 mm
2026-07-31	1167.7	1097.5	120.6 mm	137.4 mm
2026-08-01	1183.3	1109.8	120.6 mm	137.4 mm
2026-08-02	1199.7	1122.2	120.6 mm	137.4 mm
2026-08-03	1216.2	1134.4	120.6 mm	137.4 mm
2026-08-04	1230.4	1146.1	120.6 mm	137.4 mm
2026-08-05	1243.1	1157.3	120.6 mm	137.4 mm
2026-08-06	1255.7	1168.7	120.6 mm	137.4 mm
2026-08-07	1269.2	1180.2	120.6 mm	137.4 mm
2026-08-08	1282.9	1192.1	120.6 mm	137.4 mm
2026-08-09	1297.8	1204.3	120.6 mm	137.4 mm
2026-08-10	1310.1	1216.5	120.6 mm	137.4 mm
2026-08-11	1321.1	1228.8	120.6 mm	137.4 mm
2026-08-12	1330.9	1241.3	120.6 mm	137.4 mm
2026-08-13	1338.6	1254.0	120.7 mm	137.5 mm
2026-08-14	1347.5	1266.6	120.7 mm	137.5 mm
2026-08-15	1357.2	1279.0	120.7 mm	137.5 mm
2026-08-16	1368.5	1291.8	120.7 mm	137.5 mm
2026-08-17	1380.7	1304.1	120.7 mm	137.6 mm
2026-08-18	1393.3	1316.0	120.7 mm	137.6 mm
2026-08-19	1406.0	1327.4	120.7 mm	137.6 mm
2026-08-20	1417.5	1338.4	120.7 mm	138.1 mm
2026-08-21	1429.4	1349.9	120.8 mm	138.1 mm
2026-08-22	1442.0	1361.6	120.8 mm	138.3 mm
2026-08-23	1455.9	1373.4	120.8 mm	138.3 mm

Forecast outlook

ECMWF IFS 0.25° via Herbie · run Aug 30, 2026 at 00:00 UTC

10-day totals compared with the 1991–2020 combined regional record

GDD accumulation: 87 GDDvs 119 GDD average
Total rainfall: 1.5 mmvs 0.2 mm average

No unusually hot or wet period stands out in the short-range forecast.

Sun8/30 29°Cavg 30°C 12°Cavg 13°C +10 GDD 0.0 mm

Mon8/31 23°Cavg 30°C 12°Cavg 13°C +6 GDD 0.0 mm

Tue9/1 20°Cavg 31°C 12°Cavg 13°C +5 GDD 0.1 mm

Wed9/2 21°Cavg 31°C 12°Cavg 13°C +6 GDD 0.0 mm

Thu9/3 24°Cavg 31°C 12°Cavg 13°C +7 GDD 0.0 mm

Fri9/4 26°Cavg 30°C 14°Cavg 13°C +8 GDD 0.0 mm

Sat9/5 26°Cavg 31°C 12°Cavg 13°C +9 GDD 0.0 mm

Sun9/6 29°Cavg 31°C 12°Cavg 13°C +12 GDD 0.0 mm

Mon9/7 26°Cavg 31°C 17°Cavg 13°C +12 GDD 0.5 mm

Tue9/8 26°Cavg 30°C 19°Cavg 13°C +12 GDD 0.8 mm

Data and methods

Show data sources and model assumptions

Current temperature, dew point, humidity, and wind use geographically weighted NWS station observations. The 24-hour rain total and 10-day outlook use the 00 UTC deterministic ECMWF IFS 0.25° public forecast retrieved directly with Herbie. Historical temperature and rain combine qualifying GHCN-D stations with ERA5 by geographic area; a missing station day uses the nearest ERA5 value for that station's area. Climate comparisons use 1991–2020.

Forecast comparisons use the 1991–2020 combined regional daily record. Daily high and low averages use the matching date; rainfall and GDD sum the same calendar dates as the forecast period.

This service is based on data and products of the European Centre for Medium-Range Weather Forecasts (ECMWF). Weather & Vines subsets, converts, and regionally weights the forecast fields. ECMWF data are published under CC BY 4.0. ECMWF accepts no liability for errors, omissions, availability, loss, or damage arising from their use.

Climate projections use NASA NEX-GDDP-CMIP6 v2.0, accessed August 23, 2026, with 25 models. Weather & Vines subsets and aggregates the source fields. Source files and derived projection data are under CC BY-SA 4.0; the full roster and limitations are listed in the climate atlas methods.

The Napa Valley model uses a March 15–November 15 growing season, base 10°C GDD, and an operational hot-day marker of 35°C.

The historical series uses 4 ERA5 locations, 13 temperature stations, and 12 rain stations. Interpretation confidence: high. Geometry confidence: authoritative. Rules: napa-v2-2026-07.

Napa Valley

Current conditions

Vintage explorer

Moderately cooler and significantly wetter than normal.

What stood out in 2010

How unusual was 2010?

2010 month by month

Heat accumulation

Rainfall

Heat accumulation

Rainfall

Heat accumulation

Rainfall

Heat accumulation

Rainfall

Heat accumulation

Rainfall

Heat accumulation

Rainfall

Heat accumulation

Rainfall

Heat accumulation

Rainfall

Heat accumulation

Rainfall

Replay the 2010 growing season

Closest weather matches

1998

1999

1994

9.0°C

12.6°C

20.3°C

18.8°C

Weather events

Spring frost exposure

Dry spell

Heat episode

Heat episode

Heat episode

Dry spell

Heat episode

Concentrated harvest rain

Concentrated harvest rain

Climate change

Historical trends, 1991–2025

Projected climate through 2075

When to visit

Next ten days

Growing season heat and rainfall

Forecast outlook

Data and methods