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South Africa · Multi-region weather view

Stellenbosch

Cape vineyards spanning Simonsberg, Bottelary, central Stellenbosch and the Helderberg slopes.

Dry summers meet Atlantic and False Bay influence across a varied landscape. Heat, wind, water stress and late-season rain differ between inland hills and the cooler Helderberg-facing sites.

Climate comparisons use the 1991–2020 combined regional record · updated through Sep 13, 2026.

Current conditions

Observations through Sep 21, 2026 · 03:00 UTC

Temperature15.6°C
Dew Point14.6°C
Relative Humidity94%
24h Rainfall0.0 mmmodeled IFS total through Sep 20

Vintage explorer

Compare this vintage · View 1999 across regions →

Moderately warmer and significantly drier than normal.

Mean temperature18.8°C
Temperature anomaly+0.5°Cvs 1991-2020
Growing degree days2153base 10°C
Hot days1≥ 35°C

What stood out in 1999

Less rain often lowers disease pressure, but vines may depend more on stored soil water or irrigation.

Drier than baseline · Moderate confidence

Growing-season precipitation was 76 mm below the 1991–2020 baseline.

Less rain often lowers disease pressure, but vines may depend more on stored soil water or irrigation.

How unusual was 1999?

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

Growing-season temperature

5th warmest of 35 vintages Warmer than 29 of 34 other vintages 18.8°C

Growing-season rainfall

6th driest of 35 vintages Drier than 29 of 34 other vintages 253.0 mm

Heat accumulation

3rd highest of 35 vintages Higher than 32 of 34 other vintages 2154 GDD

Hot days

2nd most of 35 vintages More than 29 of 34 other vintages 1 days

1999 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

    1999 84 GDD
    Typical 108 GDD

    Rainfall

    1999 110.8 mm
    Typical 72.7 mm
    1999 freezing days
    0
    Typical
    0.0

    Heat accumulation ran behind the typical month.

  2. 1–31
    Frost watchGrowing season

    Heat accumulation

    1999 215 GDD
    Typical 180 GDD

    Rainfall

    1999 10.9 mm
    Typical 50.2 mm
    1999 freezing days
    0
    Typical
    0.0

    Drier than the typical month.

  3. 1–30
    Frost watchGrowing season

    Heat accumulation

    1999 239 GDD
    Typical 224 GDD

    Rainfall

    1999 36.0 mm
    Typical 46.6 mm
    1999 freezing days
    0
    Typical
    0.0

    Close to the typical monthly pattern.

  4. 1–31
    Growing season

    Heat accumulation

    1999 389 GDD
    Typical 303 GDD

    Rainfall

    1999 15.2 mm
    Typical 28.5 mm

    Heat accumulation ran ahead of the typical month.

  5. 1–31
    Growing seasonHarvest window

    Heat accumulation

    1999 352 GDD
    Typical 347 GDD

    Rainfall

    1999 34.3 mm
    Typical 25.1 mm

    Close to the typical monthly pattern.

  6. 1–29
    Growing seasonHarvest window

    Heat accumulation

    1999 332 GDD
    Typical 324 GDD

    Rainfall

    1999 2.6 mm
    Typical 20.8 mm

    Drier than the typical month.

  7. 1–31
    Growing seasonHarvest window

    Heat accumulation

    1999 304 GDD
    Typical 314 GDD

    Rainfall

    1999 33.1 mm
    Typical 26.8 mm

    Close to the typical monthly pattern.

  8. 1–30
    Growing seasonHarvest window

    Heat accumulation

    1999 239 GDD
    Typical 224 GDD

    Rainfall

    1999 10.1 mm
    Typical 58.7 mm

    Drier than the typical month.

View milestone calendar data as a table
Month1999 GDDTypical GDD1999 rainfallTypical rainfall1999 freezing daysTypical freezing days
September 1999 84 GDD 108 GDD 110.8 mm 72.7 mm 00.0
October 1999 215 GDD 180 GDD 10.9 mm 50.2 mm 00.0
November 1999 239 GDD 224 GDD 36.0 mm 46.6 mm 00.0
December 1999 389 GDD 303 GDD 15.2 mm 28.5 mm Outside frost windowOutside frost window
January 2000 352 GDD 347 GDD 34.3 mm 25.1 mm Outside frost windowOutside frost window
February 2000 332 GDD 324 GDD 2.6 mm 20.8 mm Outside frost windowOutside frost window
March 2000 304 GDD 314 GDD 33.1 mm 26.8 mm Outside frost windowOutside frost window
April 2000 239 GDD 224 GDD 10.1 mm 58.7 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 Sep 13, 2026.

Replay the 1999 growing season

243 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 Sep 12, 2026.

The daily weather replay is complete, but the separate weather-event scan is not currently available for this vintage.

Closest weather matches

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

  1. Closest match

    2025

    Most alike in Hot-day count and Growing degree days.

    Hot-day count
    the same: 0 days
    Growing degree days
    lower: 5 GDD

    Largest difference: Harvest precipitation — more rain

    View 2025 →

  2. Second closest

    2014

    Most alike in Hot-day count and Growing-season mean temperature.

    Hot-day count
    the same: 0 days
    Growing-season mean temperature
    cooler: 0.1°C

    Largest difference: Growing-season precipitation — less rain

    View 2014 →

  3. Third closest

    2015

    Most alike in Hot-day count and Growing degree days.

    Hot-day count
    the same: 0 days
    Growing degree days
    higher: 17 GDD

    Largest difference: Growing-season precipitation — more rain

    View 2015 →
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: 2025 0.360; 2014 0.409; 2015 0.532.

Growing-season temperature anomalyCompared with 1991-2020
Temperature anomaly by vintage, 1991 to 2026 A line above zero indicates a warmer growing season than the 1991–2020 baseline. Select a point to inspect that vintage. +2.6°C −2.6°C 1991 2000 2010 2020 2026
Growing-season rainfall anomaly
Rainfall anomaly by vintage, 1991 to 2026 Bars show millimeters above or below the 1991–2020 growing-season baseline. Select a bar to inspect that vintage. +320 mm −320 mm 1991 2000 2010 2020 2026
View historical chart data as a table
YearTemperature anomalyRainfall anomalyHot days
1991-0.4°C+92 mm0
1992-0.6°C+168 mm0
1993+0.5°C-132 mm0
1994-0.2°C-65 mm0
1995-0.5°C+22 mm0
1996-1.7°C+167 mm0
1997-0.1°C-68 mm0
1998-0.0°C-46 mm0
1999+0.5°C-76 mm1
2000-0.1°C-26 mm1
2001+0.1°C+125 mm0
2002+0.2°C-37 mm0
2003-0.3°C+55 mm0
2004+0.6°C+90 mm0
2005-0.1°C-117 mm0
2006+0.0°C-1 mm0
2007+0.0°C-4 mm0
2008-0.1°C+38 mm0
2009-0.1°C+38 mm2
2010+0.3°C-58 mm0
2011-0.1°C+36 mm0
2012+0.1°C+38 mm0
2013+0.1°C+135 mm0
2014+0.4°C-128 mm1
2015+0.6°C-13 mm1
2016+0.5°C-131 mm0
2017+0.0°C-8 mm0
2018+0.1°C-32 mm0
2019+0.4°C-47 mm0
2020-0.2°C-17 mm0
2021-0.1°C-46 mm0
2022-0.2°C+2 mm0
2023+0.3°C-43 mm0
2024+0.2°C-126 mm0
2025+0.5°C-60 mm1
2026-2.3°C-311 mm0

winter

13.0°C

+0.9°C vs baseline

338 mm rain · -31 mm

spring

15.8°C

+0.2°C vs baseline

157 mm rain · -12 mm

summer

21.8°C

+1.0°C vs baseline

52 mm rain · -22 mm

harvest

20.6°C

+0.1°C vs baseline

71 mm rain · -27 mm

Weather events

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 +39.4 GDD per decade. The 95% interval is +8.7 to +70.1 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
19911945 GDD-78 GDD
19921873 GDD-150 GDD
19932143 GDD+120 GDD
19941975 GDD-48 GDD
19951911 GDD-112 GDD
19961616 GDD-408 GDD
19972008 GDD-15 GDD
19982014 GDD-9 GDD
19992154 GDD+130 GDD
20001995 GDD-28 GDD
20012045 GDD+22 GDD
20022070 GDD+47 GDD
20031959 GDD-64 GDD
20042176 GDD+153 GDD
20051989 GDD-34 GDD
20062021 GDD-2 GDD
20072031 GDD+8 GDD
20082003 GDD-20 GDD
20092004 GDD-19 GDD
20102095 GDD+72 GDD
20111996 GDD-27 GDD
20122034 GDD+11 GDD
20132047 GDD+24 GDD
20142111 GDD+88 GDD
20152171 GDD+147 GDD
20162136 GDD+113 GDD
20172022 GDD-2 GDD
20182058 GDD+35 GDD
20192117 GDD+94 GDD
20201978 GDD-45 GDD
20212001 GDD-22 GDD
20221968 GDD-56 GDD
20232106 GDD+82 GDD
20242063 GDD+39 GDD
20252149 GDD+125 GDD
Growing-season mean temperature
+0.16 °C per decade 95% interval +0.04 to +0.29
Growing degree days
+39.39 GDD per decade 95% interval +8.70 to +70.08
Growing-season precipitation
-24.85 mm per decade 95% interval -42.21 to -7.50
Hot days
+0.04 days per decade 95% interval -0.08 to +0.17
Spring frost days
No variation recorded
Longest dry spell
-0.97 days per decade 95% interval -3.33 to +1.38

Last Updated September 13, 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+0.5°C+0.3 to +0.7°C25
2041-2060+1.0°C+0.7 to +1.3°C25
2061-2075+1.3°C+0.9 to +1.7°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

ECMWF IFS 0.25° via Herbie · model run Sep 20, 2026 at 00:00 UTC · retrieved Sep 21, 2026 at 03:23 UTC

Scroll horizontally to see all forecast dates.

DateMonTueWedThuFriSatSunMonTueWed
High 29°C 31°C 27°C 21°C 18°C 18°C 19°C 21°C 23°C 14°C
Low 15°C 17°C 17°C 16°C 14°C 14°C 13°C 15°C 14°C 14°C
Rain 0.1 mm 7.9 mm 0.0 mm 0.0 mm 20.8 mm 7.5 mm 0.1 mm 1.8 mm 0.0 mm 0.0 mm

Across the typical year: Late February has the warmest median afternoon high (25.8°C); Early August has the coolest (15.1°C). Wet days are most frequent in Early June (40%) and least frequent in Late February (11%). 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 Stellenbosch 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. 5°C10°C15°C20°C25°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 Stellenbosch 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.

Stellenbosch 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 1–1525.2°C (23.1–27.8°C)16.4°C (15.3–17.6°C)14%7.9 mm (4.4–20.2 mm)
Jan 16–3125.6°C (23.7–28.2°C)16.8°C (15.6–18.0°C)12%7.2 mm (3.3–15.4 mm)
Feb 1–1525.7°C (23.7–28.5°C)17.1°C (15.9–18.2°C)16%10.6 mm (4.9–16.4 mm)
Feb 16–2925.8°C (23.6–28.4°C)16.9°C (15.8–18.0°C)11%5.4 mm (2.4–10.3 mm)
Mar 1–1525.2°C (22.8–27.8°C)16.3°C (15.1–17.5°C)12%8.0 mm (2.8–14.2 mm)
Mar 16–3123.7°C (21.8–26.0°C)15.3°C (14.2–16.3°C)16%8.4 mm (5.5–18.0 mm)
Apr 1–1522.8°C (20.2–25.5°C)14.0°C (12.5–15.3°C)20%15.2 mm (8.2–33.6 mm)
Apr 16–3020.4°C (18.1–23.2°C)12.3°C (10.8–13.7°C)23%34.9 mm (10.8–50.8 mm)
May 1–1519.4°C (17.3–21.9°C)11.5°C (10.1–12.7°C)27%25.3 mm (9.9–35.2 mm)
May 16–3117.5°C (15.7–20.0°C)10.5°C (9.0–11.9°C)36%55.0 mm (37.0–77.9 mm)
Jun 1–1515.9°C (14.4–18.0°C)9.1°C (7.4–10.8°C)40%66.8 mm (45.6–101.8 mm)
Jun 16–3015.4°C (14.0–17.8°C)8.3°C (6.8–9.7°C)37%54.4 mm (27.1–74.3 mm)
Jul 1–1515.4°C (13.6–18.2°C)8.0°C (6.3–9.5°C)36%56.7 mm (21.2–83.0 mm)
Jul 16–3115.2°C (13.4–17.5°C)7.7°C (6.2–9.3°C)34%52.6 mm (29.3–95.8 mm)
Aug 1–1515.1°C (13.6–17.4°C)7.9°C (6.4–9.4°C)38%47.4 mm (32.8–74.6 mm)
Aug 16–3115.7°C (13.8–18.3°C)8.3°C (6.9–10.0°C)37%52.6 mm (26.7–64.3 mm)
Sep 1–1516.6°C (14.8–19.1°C)9.4°C (8.0–10.6°C)32%28.5 mm (15.3–50.1 mm)
Sep 16–3017.3°C (15.3–20.1°C)9.8°C (8.3–11.4°C)32%28.6 mm (22.7–49.9 mm)
Oct 1–1519.1°C (16.6–21.7°C)11.0°C (9.6–12.4°C)24%16.2 mm (9.8–26.3 mm)
Oct 16–3120.1°C (17.7–23.2°C)12.2°C (10.7–13.6°C)25%20.9 mm (10.4–44.6 mm)
Nov 1–1521.2°C (18.7–23.9°C)13.1°C (11.7–14.2°C)25%17.0 mm (9.4–39.2 mm)
Nov 16–3022.0°C (19.8–24.7°C)13.4°C (12.3–14.7°C)20%15.1 mm (10.3–25.9 mm)
Dec 1–1523.8°C (21.6–26.3°C)15.0°C (13.8–16.3°C)17%9.2 mm (4.5–15.4 mm)
Dec 16–3124.1°C (22.0–26.5°C)15.7°C (14.4–16.9°C)18%12.4 mm (7.7–18.6 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 September 13, 2026

Season to date

Growing season heat and rainfall

Sep 1–Sep 20, 2026

Compare this season across regions →

Growing degree days78.2base 10°C
Growing-season rainfall18.9 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. 78 GDD 0 Sep ’26
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. 32 mm 0 Sep ’26
View growing-season accumulation data
DateSeason GDD1991–2020 average GDDSeason rainfall1991–2020 average rainfall
2026-09-011.93.00.0 mm2.4 mm
2026-09-024.96.10.0 mm5.7 mm
2026-09-037.09.02.1 mm8.0 mm
2026-09-0412.012.12.3 mm9.2 mm
2026-09-0517.215.12.3 mm13.6 mm
2026-09-0625.318.52.3 mm14.4 mm
2026-09-0734.422.02.3 mm17.6 mm
2026-09-0843.925.32.3 mm21.6 mm
2026-09-0951.628.12.3 mm25.5 mm
2026-09-1057.030.92.3 mm28.1 mm
2026-09-1164.134.22.3 mm29.2 mm
2026-09-1270.037.912.0 mm30.8 mm
2026-09-1378.242.018.9 mm32.3 mm

Forecast outlook

ECMWF IFS 0.25° via Herbie · run Sep 20, 2026 at 00:00 UTC

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

GDD accumulation
78 GDDvs 39 GDD average
Total rainfall
38.3 mmvs 22.5 mm average

A notable amount of rain is forecast during the period. The 10-day total meets the 30 mm forecast threshold, with rain forecast Sep 21–23 and Sep 25–28.

Mon9/21 29°Cavg 18°C 15°Cavg 10°C +12 GDD 0.1 mm
Tue9/22 31°Cavg 19°C 17°Cavg 10°C +14 GDD 7.9 mm
Wed9/23 27°Cavg 18°C 17°Cavg 10°C +10 GDD 0.0 mm
Thu9/24 21°Cavg 17°C 16°Cavg 10°C +8 GDD 0.0 mm
Fri9/25 18°Cavg 18°C 14°Cavg 10°C +6 GDD 20.8 mm
Sat9/26 18°Cavg 17°C 14°Cavg 10°C +5 GDD 7.5 mm
Sun9/27 19°Cavg 17°C 13°Cavg 10°C +6 GDD 0.1 mm
Mon9/28 21°Cavg 18°C 15°Cavg 9°C +7 GDD 1.8 mm
Tue9/29 23°Cavg 19°C 14°Cavg 10°C +7 GDD 0.0 mm
Wed9/30 14°Cavg 19°C 14°Cavg 10°C +4 GDD 0.0 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 September 20, 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 Stellenbosch model uses a September 1–April 30 growing season, base 10°C GDD, and an operational hot-day marker of 35°C.