Climate averages 1991–2020
Johannesburg weather
in September.
A warm, fairly dry month: the 6th warmest and the 5th driest of the year. Meets the pleasant-weather rule
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Johannesburg: daytime highs average 23.4°C and nights cool to about 8.5°C. By daytime temperature it is the 6th warmest of the 12 months.
Expect about 22 mm of rain on roughly 4 days, which makes September a fairly dry month (the 5th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 11 h 55 min on an average September day.
The nearest other city in this atlas is Alberton (11 km away). In September its highs average 24.7°C, 1.3°C warmer than Johannesburg, with 22 mm of rain.
Among the 95 cities listed in South Africa, Johannesburg ranks joint 70th of 95 for the warmest September highs and joint 47th of 95 for the driest September (rainfall, lowest first). The mean September high of those 95 cities is 24.3°C; Johannesburg is 0.8°C cooler than that mean.
From September to October, average highs rise by 1.0°C to 24.4°C, and monthly rainfall rises from 22 mm to 75 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Johannesburg climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 24.3°C14.1°C | 14.1°C | 132 | 16.4 | 13.614 h |
| February | 24.1°C13.9°C | 13.9°C | 111 | 14.1 | 13.013 h |
| March | 22.8°C12.3°C | 12.3°C | 89 | 12.7 | 12.312 h |
| April | 20.4°C9.3°C | 9.3°C | 45 | 7.3 | 11.511 h |
| May | 18.4°C5.7°C | 5.7°C | 17 | 2.9 | 10.911 h |
| June | 16.1°C2.9°C | 2.9°C | 7.8 | 1.3 | 10.511 h |
| July | 16.3°C2.2°C | 2.2°C | 3.0 | 0.8 | 10.711 h |
| August | 19.4°C4.9°C | 4.9°C | 9.8 | 2.0 | 11.211 h |
| September, selected | 23.4°C8.5°C | 8.5°C | 22 | 3.7 | 11.912 h |
| October | 24.4°C10.9°C | 10.9°C | 75 | 10.7 | 12.713 h |
| November | 24.1°C12.3°C | 12.3°C | 100 | 14.0 | 13.413 h |
| December | 24.3°C13.7°C | 13.7°C | 138 | 18.0 | 13.714 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Alberton in SeptemberSouth Africa · 11 kmHigh 24.7°C · Low 9.5°C · 22 mm rain
- Germiston in SeptemberSouth Africa · 12 kmHigh 24.5°C · Low 9.3°C · 23 mm rain
- Randburg in SeptemberSouth Africa · 13 kmHigh 24.6°C · Low 9.5°C · 19 mm rain
- Roodepoort in SeptemberSouth Africa · 18 kmHigh 23.6°C · Low 8.5°C · 21 mm rain
- Tokoza in SeptemberSouth Africa · 19 kmHigh 24.9°C · Low 9.5°C · 23 mm rain
- Soweto in SeptemberSouth Africa · 20 kmHigh 24.2°C · Low 9.3°C · 21 mm rain
- Midrand in SeptemberSouth Africa · 26 kmHigh 24.4°C · Low 9.4°C · 19 mm rain
- Benoni in SeptemberSouth Africa · 28 kmHigh 24.4°C · Low 9.2°C · 23 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Johannesburg) is explained once on the Johannesburg year overview and on the Sources, method and limits page.
Alberton lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.