Johannesburg weather in August
In August, Johannesburg has daytime highs averaging 20 °C, nights around 5.0 °C, with 2.0 wet days. Figures are 1991–2020 climate normals.
- 19.5°C Average high
- 5.0°C Average low
- 2.0days Wet days
- 10mm Rainfall
- 11h Daylight
Daily temperatures through August
How August develops
Averages for the first, middle and last part of the month, from daily 1991–2020 normals. Chance of rain is the share of years in which that calendar day recorded more than 1 mm.
| Days | Avg high | Avg low | Chance of rain |
|---|---|---|---|
| 1–10 August | 18.1 °C | 3.9 °C | 5 % |
| 11–20 August | 19.3 °C | 4.7 °C | 6 % |
| 21–31 August | 20.9 °C | 6.2 °C | 8 % |
- Average highs rise from 18.1 °C early in August to 20.9 °C by the end of it.
What to expect
| Measure | Typical August | Share of the month |
|---|---|---|
| Days above 25 °C | 1.0 of 31 | 3 % |
| Days above 30 °C | 0 of 31 | 0 % |
| Days below 0 °C | 1.6 of 31 | 5 % |
| Days with more than 1 mm rain | 2.0 of 31 | 6 % |
Conditions in August
| Measure | Average |
|---|---|
| Mean temperature | 12 °C |
| Record high (1991–2020) | 27 °C |
| Record low (1991–2020) | -4.0 °C |
| Relative humidity | 45 % |
| Wind speed | 18 km/h |
| Cloud cover | 16 % |
Where Johannesburg ranks in August
| Ranking | Position | Value |
|---|---|---|
| The coolest places in Africa in August | 12th of 50 | 20 °C |
August compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| June | 16.3 °C | 8 mm | 15 % |
| July | 16.4 °C | 3 mm | 12 % |
| August | 19.5 °C | 10 mm | 16 % |
| September | 23.5 °C | 22 mm | 24 % |
| October | 24.6 °C | 73 mm | 40 % |
See all twelve months for Johannesburg
- August is the 9th warmest month here.
- It is the 3rd driest month of the year.
- It ranks 3rd for least cloud cover.
- Days last about 11 hours from sunrise to sunset.
- It rains on 2.0 of 31 days — 6 % of the month.
- Nights are about 15 °C cooler than the middle of the day.
- The hottest August day on record since 1991 reached 27 °C, 7.7 °C above the usual daytime high.
QuestionsAugust in Johannesburg, answered
How warm is Johannesburg in August?
Daily highs average 20 °C and nights fall to about 5.0 °C, a spread of 15 °C between afternoon and dawn. That makes August the 9th warmest month of the year here.
Does it rain much in Johannesburg in August?
August averages 10 mm of rain, spread over about 2 of the 31 days — 6 % of the month. Cloud cover averages 16 % of the sky.
How long are the days in August?
Johannesburg averages 11 hours between sunrise and sunset in August. Day length is computed from latitude and date, so it is exact rather than modelled — but it says nothing about how much of that time is sunny.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: daylight hours, beach and comfort scores, monthly rankings, threshold day counts, chance of a wet day by date, ten-day averages within the month. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.