This site is in beta. Please report problems here.
Display
Climate baseline
Units
Color theme

South Africa · Multi-region weather view

Swartland

South African vineyards around Malmesbury, the Riebeek valley and the Piketberg area, known especially for Chenin Blanc and Syrah.

Hot, dry summers and winter rainfall make stored soil moisture important. Hills, exposure and distance from the Atlantic create differences that a regional record smooths.

Climate comparisons use the 1991–2020 combined regional record · updated through Oct 17, 2026.

Current conditions

Model estimate valid Nov 3, 2026 · 06:00 UTC

Regional model estimate averaged across the configured sampling locations.

Temperature19.1°C
Dew Point11.3°C
Relative Humidity60%
24h RainfallUnavailable

Vintage explorer

Compare this vintage · View 2018 across regions →

Slightly cooler and moderately drier than normal.

Mean temperature20.5°C
Temperature anomaly-0.1°Cvs 1991-2020
Growing degree days2543base 10°C
Hot days18≥ 35°C

What stood out in 2018

No single weather pattern stands out in the regional record.

Close to the usual range · Low confidence

Temperature, rainfall, heat, and frost all stayed within the site's published thresholds.

No single weather pattern stands out in the regional record.

How unusual was 2018?

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

Growing-season temperature

13th coolest of 35 vintages Cooler than 21 of 34 other vintages 20.5°C

Growing-season rainfall

14th driest of 35 vintages Drier than 21 of 34 other vintages 193.6 mm

Heat accumulation

13th lowest of 35 vintages Lower than 22 of 34 other vintages 2544 GDD

Hot days

13th fewest of 35 vintages Fewer than 19 of 34 other vintages 18 days

2018 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
  1. 1–30
    Frost watchGrowing season

    Heat accumulation

    2018 95 GDD
    Typical 133 GDD

    Rainfall

    2018 79.9 mm
    Typical 54.0 mm
    2018 freezing days
    0
    Typical
    0.0

    Heat accumulation ran behind the typical month.

  2. 1–31
    Frost watchGrowing season

    Heat accumulation

    2018 324 GDD
    Typical 237 GDD

    Rainfall

    2018 16.4 mm
    Typical 34.8 mm
    2018 freezing days
    0
    Typical
    0.0

    Heat accumulation ran ahead of the typical month.

  3. 1–30
    Frost watchGrowing season

    Heat accumulation

    2018 306 GDD
    Typical 297 GDD

    Rainfall

    2018 9.6 mm
    Typical 30.6 mm
    2018 freezing days
    0
    Typical
    0.0

    Drier than the typical month.

  4. 1–31
    Growing season

    Heat accumulation

    2018 362 GDD
    Typical 389 GDD

    Rainfall

    2018 29.9 mm
    Typical 18.7 mm

    Wetter than the typical month.

  5. 1–31
    Growing seasonHarvest window

    Heat accumulation

    2018 405 GDD
    Typical 441 GDD

    Rainfall

    2018 16.4 mm
    Typical 14.7 mm

    Close to the typical monthly pattern.

  6. 1–28
    Growing seasonHarvest window

    Heat accumulation

    2018 422 GDD
    Typical 404 GDD

    Rainfall

    2018 8.2 mm
    Typical 12.2 mm

    Close to the typical monthly pattern.

  7. 1–31
    Growing seasonHarvest window

    Heat accumulation

    2018 370 GDD
    Typical 388 GDD

    Rainfall

    2018 16.7 mm
    Typical 18.0 mm

    Close to the typical monthly pattern.

  8. 1–30
    Growing seasonHarvest window

    Heat accumulation

    2018 260 GDD
    Typical 273 GDD

    Rainfall

    2018 16.3 mm
    Typical 40.4 mm

    Drier than the typical month.

View milestone calendar data as a table
Month2018 GDDTypical GDD2018 rainfallTypical rainfall2018 freezing daysTypical freezing days
September 2018 95 GDD 133 GDD 79.9 mm 54.0 mm 00.0
October 2018 324 GDD 237 GDD 16.4 mm 34.8 mm 00.0
November 2018 306 GDD 297 GDD 9.6 mm 30.6 mm 00.0
December 2018 362 GDD 389 GDD 29.9 mm 18.7 mm Outside frost windowOutside frost window
January 2019 405 GDD 441 GDD 16.4 mm 14.7 mm Outside frost windowOutside frost window
February 2019 422 GDD 404 GDD 8.2 mm 12.2 mm Outside frost windowOutside frost window
March 2019 370 GDD 388 GDD 16.7 mm 18.0 mm Outside frost windowOutside frost window
April 2019 260 GDD 273 GDD 16.3 mm 40.4 mm Outside frost windowOutside 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 Oct 17, 2026.

Replay the 2018 growing season

242 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 Oct 17, 2026.

Closest weather matches

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

  1. Closest match

    1994

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

    Growing-season mean temperature
    cooler: 0.0°C
    Growing degree days
    lower: 15 GDD

    Largest difference: Harvest precipitation — less rain

    View 1994 →

  2. Second closest

    2021

    Most alike in Harvest precipitation and Growing-season mean temperature.

    Harvest precipitation
    more rain: 2.4 mm
    Growing-season mean temperature
    cooler: 0.1°C

    Largest difference: Growing-season precipitation — more rain

    View 2021 →

  3. Third closest

    2017

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

    Growing-season mean temperature
    the same: 0.0°C
    Growing degree days
    lower: 8 GDD

    Largest difference: Hot-day count — more hot days

    View 2017 →
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%). Measures omitted because they did not vary: Spring frost exposure.

Calculated distances: 1994 0.267; 2021 0.321; 2017 0.376.

Growing-season temperature anomalyCompared with 1991-2020
Temperature anomaly by vintage, 1991 to 2025 A line above zero indicates a warmer growing season than the 1991–2020 baseline. Select a point to inspect that vintage. +2.4°C −2.4°C 1991 2000 2010 2020 2025
Growing-season rainfall anomaly
Rainfall anomaly by vintage, 1991 to 2025 Bars show millimeters above or below the 1991–2020 growing-season baseline. Select a bar to inspect that vintage. +150 mm −150 mm 1991 2000 2010 2020 2025
View historical chart data as a table
YearTemperature anomalyRainfall anomalyHot days
1991-0.8°C+113 mm10
1992-0.8°C+90 mm18
1993+0.8°C-100 mm20
1994-0.1°C-43 mm19
1995-0.4°C+9 mm19
1996-2.1°C+138 mm2
1997+0.1°C-63 mm14
1998+0.1°C-32 mm20
1999+0.8°C-32 mm23
2000-0.1°C+5 mm13
2001-0.2°C+111 mm12
2002+0.3°C-29 mm16
2003-0.3°C+96 mm19
2004+0.7°C+14 mm18
2005+0.0°C-60 mm14
2006+0.0°C-1 mm10
2007+0.1°C-8 mm20
2008+0.0°C+15 mm20
2009-0.1°C+27 mm18
2010+0.5°C-22 mm19
2011-0.1°C+12 mm19
2012+0.4°C+44 mm29
2013+0.2°C+68 mm24
2014+0.1°C-89 mm14
2015+0.7°C-32 mm33
2016+0.4°C-87 mm21
2017-0.1°C-18 mm22
2018-0.1°C-30 mm18
2019+0.4°C-59 mm21
2020-0.2°C-37 mm13
2021-0.2°C-4 mm20
2022-0.5°C+36 mm8
2023+0.2°C-26 mm21
2024-0.0°C-77 mm10
2025+0.3°C-42 mm19

winter

12.5°C

+0.3°C vs baseline

260 mm rain · -16 mm

spring

17.9°C

+0.6°C vs baseline

105 mm rain · -13 mm

summer

23.2°C

-0.5°C vs baseline

54 mm rain · +9 mm

harvest

22.6°C

-0.6°C vs baseline

54 mm rain · -8 mm

Weather events

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

  1. Heat episode

    Peak temperature
    37.1°C
    Duration
    3 days
    Heat accumulation
    51 GDD

  2. Heat episode

    Peak temperature
    38.8°C
    Duration
    3 days
    Heat accumulation
    51 GDD

  3. Dry spell

    Duration
    27 days
    Total rain
    2.1 mm
    Daily cutoff
    1.0 mm/day

  4. Dry spell

    Duration
    14 days
    Total rain
    0.4 mm
    Daily cutoff
    1.0 mm/day

  5. Dry spell

    Duration
    15 days
    Total rain
    0.8 mm
    Daily cutoff
    1.0 mm/day

  6. Heat episode

    Peak temperature
    39.1°C
    Duration
    2 days
    Heat accumulation
    38 GDD

  7. Dry spell

    Duration
    22 days
    Total rain
    0.3 mm
    Daily cutoff
    1.0 mm/day

  8. Heat episode

    Peak temperature
    39.6°C
    Duration
    3 days
    Heat accumulation
    53 GDD

  9. Dry spell

    Duration
    22 days
    Total rain
    0.8 mm
    Daily cutoff
    1.0 mm/day
How events are detected

Weather & Vines combined regional series; method event-timeline-v2-2026-07, rules swartland-catalog-v1-2026-10. Source last updated Oct 17, 2026, calculated Oct 18, 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 +32.5 GDD per decade. The 95% interval is -6.6 to +71.6 GDD per decade, based on 35 eligible vintages.

How it is measured: Across the September 1–April 30 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
VintageGrowing degree daysChange from 1991–2020
19912375 GDD-188 GDD
19922375 GDD-188 GDD
19932741 GDD+178 GDD
19942529 GDD-34 GDD
19952476 GDD-87 GDD
19962043 GDD-520 GDD
19972580 GDD+16 GDD
19982578 GDD+15 GDD
19992767 GDD+204 GDD
20002546 GDD-17 GDD
20012515 GDD-48 GDD
20022625 GDD+62 GDD
20032486 GDD-77 GDD
20042726 GDD+163 GDD
20052566 GDD+3 GDD
20062560 GDD-4 GDD
20072592 GDD+29 GDD
20082567 GDD+4 GDD
20092532 GDD-31 GDD
20102689 GDD+125 GDD
20112544 GDD-19 GDD
20122655 GDD+92 GDD
20132602 GDD+39 GDD
20142594 GDD+31 GDD
20152737 GDD+174 GDD
20162654 GDD+91 GDD
20172536 GDD-28 GDD
20182544 GDD-20 GDD
20192659 GDD+96 GDD
20202503 GDD-60 GDD
20212499 GDD-65 GDD
20222444 GDD-119 GDD
20232633 GDD+70 GDD
20242557 GDD-7 GDD
20252645 GDD+82 GDD
Growing-season mean temperature
+0.14 °C per decade 95% interval -0.03 to +0.30
Growing degree days
+32.50 GDD per decade 95% interval -6.65 to +71.64
Growing-season precipitation
-19.82 mm per decade 95% interval -34.48 to -5.16
Hot days
+1.06 days per decade 95% interval -0.78 to +2.90
Spring frost days
No variation recorded
Longest dry spell
+1.41 days per decade 95% interval -1.39 to +4.20

Last Updated October 17, 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.

PeriodWeighted medianWeighted central 80%Models per pathway
2021-2040+0.6°C+0.3 to +0.8°C25
2041-2060+1.1°C+0.8 to +1.5°C25
2061-2075+1.4°C+1.0 to +2.0°C25
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

Regional average across 3 sampling locations.

ECMWF IFS 0.25° via Herbie · model run Nov 3, 2026 at 00:00 UTC · retrieved Nov 3, 2026 at 08:24 UTC

Scroll horizontally to see all forecast dates.

DateTueWedThuFriSatSunMonTueWedThu
High 31°C 35°C 25°C 22°C 23°C 29°C 32°C 27°C 23°C 24°C
Low 14°C 16°C 16°C 14°C 11°C 12°C 16°C 15°C 17°C 16°C
Rain 0.0 mm 0.0 mm 0.6 mm 3.1 mm 0.1 mm 0.0 mm 0.0 mm 0.0 mm 4.5 mm 2.6 mm

Across the typical year: Late January has the warmest median afternoon high (31.2°C); Early August has the coolest (16.8°C). Wet days are most frequent in Early June (35%) and least frequent in Late February (7%). 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.

Typical afternoon highs and overnight lows for Swartland Median daily maximum and minimum temperatures for 24 early and late-month periods under the 1991–2020 baseline. Neutral bands show the 25th to 75th percentile. 0°C10°C20°C30°C JanFebMarAprMayJunJulAugSepOctNovDec
How often a day is wetShare of days with at least 1 mm of rain

Scroll horizontally to inspect all 24 half-month periods.

Wet-day frequency through the typical year for Swartland The fraction of days receiving at least one millimeter of rain in each early and late-month period under the 1991–2020 baseline. 0%25%50%75%100% JanFebMarAprMayJunJulAugSepOctNovDec
View all 24 periods as a table

Scroll horizontally to view all columns.

Swartland typical weather by half-month, 1991–2020
PeriodAfternoon high, median (middle 50%)Overnight low, median (middle 50%)Wet-day frequencyPeriod rain, median (middle 50%)
Jan 1–1530.8°C (28.0–33.7°C)17.0°C (15.7–18.4°C)9%4.4 mm (1.7–12.1 mm)
Jan 16–3131.2°C (28.5–34.3°C)17.6°C (16.1–19.0°C)8%4.6 mm (1.4–10.7 mm)
Feb 1–1531.1°C (28.5–34.2°C)17.5°C (16.0–19.0°C)10%4.9 mm (2.1–11.1 mm)
Feb 16–2931.0°C (28.4–34.2°C)17.2°C (15.8–18.8°C)7%2.0 mm (0.9–5.1 mm)
Mar 1–1530.4°C (27.2–33.0°C)16.4°C (14.9–18.1°C)8%4.8 mm (1.1–8.3 mm)
Mar 16–3128.6°C (26.0–31.1°C)15.1°C (13.9–16.5°C)11%6.0 mm (2.7–18.2 mm)
Apr 1–1527.2°C (23.7–30.3°C)13.7°C (11.8–15.4°C)15%10.7 mm (5.4–21.3 mm)
Apr 16–3023.9°C (21.0–27.4°C)11.4°C (9.3–13.3°C)20%20.2 mm (6.3–36.4 mm)
May 1–1522.1°C (19.7–25.4°C)10.3°C (8.7–11.9°C)20%15.8 mm (4.7–24.4 mm)
May 16–3119.9°C (17.6–23.2°C)9.0°C (7.1–11.2°C)29%38.6 mm (24.9–49.6 mm)
Jun 1–1517.8°C (16.0–20.4°C)7.3°C (4.7–9.9°C)35%48.6 mm (33.5–75.9 mm)
Jun 16–3017.1°C (15.5–20.0°C)6.3°C (4.1–8.6°C)34%35.1 mm (23.0–57.4 mm)
Jul 1–1517.5°C (15.1–20.5°C)5.8°C (3.8–8.2°C)29%34.7 mm (16.6–62.7 mm)
Jul 16–3117.0°C (15.0–19.7°C)5.9°C (3.5–8.2°C)30%37.3 mm (18.6–72.9 mm)
Aug 1–1516.8°C (15.1–19.5°C)6.3°C (4.1–8.5°C)33%36.3 mm (23.4–58.7 mm)
Aug 16–3117.7°C (15.3–20.7°C)6.9°C (4.9–9.0°C)32%40.1 mm (20.7–52.7 mm)
Sep 1–1519.3°C (16.9–22.2°C)8.1°C (6.4–9.9°C)28%20.4 mm (11.6–34.7 mm)
Sep 16–3020.3°C (17.6–23.8°C)8.9°C (6.8–10.9°C)28%24.2 mm (15.5–36.4 mm)
Oct 1–1522.7°C (19.9–26.2°C)10.5°C (8.6–12.2°C)19%11.8 mm (5.1–19.8 mm)
Oct 16–3125.0°C (21.5–28.5°C)12.0°C (10.2–13.7°C)19%14.9 mm (7.6–29.4 mm)
Nov 1–1525.8°C (22.6–29.2°C)13.2°C (11.4–14.4°C)20%10.0 mm (5.8–29.4 mm)
Nov 16–3027.2°C (24.2–30.5°C)13.6°C (12.1–15.2°C)15%8.7 mm (5.4–15.7 mm)
Dec 1–1529.4°C (26.6–31.8°C)15.4°C (13.9–17.2°C)11%4.7 mm (1.6–9.0 mm)
Dec 16–3129.4°C (26.6–32.4°C)16.2°C (14.4–17.6°C)13%8.7 mm (4.0–14.6 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 October 17, 2026

Season to date

Growing season heat and rainfall

Sep 1–Nov 2, 2026

Compare this season across regions →

Growing degree days461.7base 10°C
Growing-season rainfall88.1 mmweighted regional total
Cumulative growing degree daysBase 10°C

2026 season1991–2020 average

Growing degree days accumulated during the 2026 growing season The solid line accumulates daily mean temperature above 10 degrees Celsius from the configured growing-season start. The dashed line shows the 1991–2020 daily climatological average. 462 GDD 0 Sep ’26OctNov
Cumulative growing-season rainfallRegional weighted mean

2026 season1991–2020 average

Rainfall accumulated during the 2026 growing season The solid line accumulates daily rainfall in millimeters from the configured growing-season start. The dashed line shows the 1991–2020 daily climatological average. 88 mm 0 Sep ’26OctNov
View growing-season accumulation data
DateSeason GDD1991–2020 average GDDSeason rainfall1991–2020 average rainfall
2026-09-012.73.50.0 mm1.8 mm
2026-09-026.37.10.0 mm4.1 mm
2026-09-039.810.52.9 mm5.6 mm
2026-09-0417.114.32.9 mm6.7 mm
2026-09-0524.718.02.9 mm9.9 mm
2026-09-0635.722.02.9 mm10.4 mm
2026-09-0747.226.12.9 mm12.3 mm
2026-09-0859.130.22.9 mm14.5 mm
2026-09-0969.833.62.9 mm18.1 mm
2026-09-1077.737.32.9 mm20.1 mm
2026-09-1187.641.32.9 mm20.9 mm
2026-09-1295.745.75.5 mm22.3 mm
2026-09-13104.850.716.2 mm23.4 mm
2026-09-14110.855.825.8 mm24.6 mm
2026-09-15116.160.933.3 mm26.4 mm
2026-09-16121.366.143.6 mm28.5 mm
2026-09-17126.971.043.6 mm31.5 mm
2026-09-18133.375.343.6 mm35.2 mm
2026-09-19142.579.943.6 mm36.7 mm
2026-09-20153.984.443.6 mm37.9 mm
2026-09-21166.089.243.6 mm39.5 mm
2026-09-22179.894.443.9 mm40.0 mm
2026-09-23189.099.044.6 mm41.4 mm
2026-09-24199.3103.744.6 mm43.0 mm
2026-09-25209.2108.644.8 mm45.9 mm
2026-09-26219.1113.057.5 mm47.9 mm
2026-09-27226.7117.257.5 mm51.9 mm
2026-09-28233.9121.957.5 mm52.9 mm
2026-09-29244.4127.157.5 mm53.4 mm
2026-09-30257.2133.157.5 mm54.1 mm
2026-10-01268.4139.257.5 mm54.6 mm
2026-10-02275.9145.657.8 mm55.5 mm
2026-10-03284.2151.957.8 mm56.4 mm
2026-10-04295.6158.257.8 mm56.9 mm
2026-10-05307.2164.557.8 mm57.7 mm
2026-10-06310.8171.366.7 mm58.6 mm
2026-10-07314.9177.966.7 mm59.9 mm
2026-10-08320.0184.466.7 mm60.7 mm
2026-10-09326.7191.166.7 mm61.2 mm
2026-10-10336.4197.666.7 mm62.3 mm
2026-10-11346.6204.366.7 mm64.3 mm
2026-10-12352.9211.368.0 mm65.9 mm
2026-10-13360.1219.168.5 mm66.3 mm
2026-10-14366.1226.968.5 mm67.2 mm
2026-10-15373.8234.568.5 mm68.1 mm
2026-10-16383.9242.068.5 mm69.1 mm
2026-10-17390.0250.570.6 mm69.5 mm
2026-10-18394.9258.970.7 mm71.1 mm
2026-10-19398.5267.470.8 mm73.6 mm
2026-10-20402.1275.773.0 mm75.7 mm
2026-10-21408.3283.883.2 mm77.1 mm
2026-10-22414.4292.188.1 mm77.8 mm
2026-10-23422.5300.588.1 mm79.0 mm
2026-10-24432.4308.688.1 mm80.7 mm
2026-10-25443.6316.888.1 mm82.2 mm
2026-10-26453.4325.788.1 mm82.6 mm
2026-10-27461.7334.988.1 mm84.1 mm

Forecast outlook

ECMWF IFS 0.25° via Herbie · run Nov 3, 2026 at 00:00 UTC

Regional average across 3 sampling locations. Daily highs and lows are averages of the locations’ daily highs and lows.

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

GDD accumulation
102 GDDvs 91 GDD average
Total rainfall
10.9 mmvs 14.1 mm average

The forecast includes a period of potentially stressful heat. The region's 35°C heat threshold is reached Nov 4.

Tue11/3 31°Cavg 25°C 14°Cavg 13°C +12 GDD 0.0 mm
Wed11/4 35°Cavg 25°C 16°Cavg 12°C +15 GDD 0.0 mm
Thu11/5 25°Cavg 24°C 16°Cavg 12°C +10 GDD 0.6 mm
Fri11/6 22°Cavg 25°C 14°Cavg 12°C +7 GDD 3.1 mm
Sat11/7 23°Cavg 27°C 11°Cavg 12°C +7 GDD 0.1 mm
Sun11/8 29°Cavg 25°C 12°Cavg 13°C +10 GDD 0.0 mm
Mon11/9 32°Cavg 26°C 16°Cavg 13°C +14 GDD 0.0 mm
Tue11/10 27°Cavg 26°C 15°Cavg 12°C +10 GDD 0.0 mm
Wed11/11 23°Cavg 27°C 17°Cavg 13°C +9 GDD 4.5 mm
Thu11/12 24°Cavg 26°C 16°Cavg 13°C +8 GDD 2.6 mm

Data and methods

Show data sources and model assumptions

Current model conditions and the 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 November 2, 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 Swartland model uses a September 1–April 30 growing season, base 10°C GDD, and an operational hot-day marker of 35°C.