Johannesburg
South Africa
| Season | Autumn | Winter | Spring | Summer | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Sep | Oct | Nov | Dec | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Year |
| Record high, °C | 30 | 31 | 32 | 32 | 32 | 33 | 31 | 28 | 27 | 23 | 22 | 26 | 33 |
| Average high, °C | 24 | 25 | 26 | 26 | 26 | 26 | 25 | 23 | 21 | 18 | 18 | 21 | 23 |
| Average temperature, °C | 17 | 18 | 20 | 21 | 21 | 21 | 20 | 17 | 14 | 10 | 11 | 13 | 17 |
| Average low, °C | 8 | 11 | 13 | 14 | 14 | 14 | 13 | 9 | 5 | 2 | 2 | 5 | 9 |
| Record low, °C | -1 | 2 | 2 | 8 | 7 | 8 | 2 | -2 | -1 | -7 | -5 | -2 | -7 |
| Fog, days | 3 | 3 | 4 | 3 | 2 | 3 | 5 | 5 | 5 | 5 | 5 | 5 | 48 |
| Thunderstorms, days | 3 | 8 | 10 | 12 | 12 | 8 | 8 | 4 | 1 | 1 | 1 | 1 | 69 |
| Average precipitation, mm. | 29 | 78 | 112 | 108 | 133 | 87 | 94 | 48 | 9 | 10 | 6 | 7 | 720 |
| Relative humidity, % | 47 | 54 | 62 | 64 | 66 | 67 | 66 | 64 | 56 | 54 | 50 | 47 | 58 |
| Relative humidity morning, % | 68 | 77 | 82 | 84 | 85 | 88 | 85 | 80 | 70 | 70 | 68 | 66 | 77 |
| Relative humidity evening, % | 34 | 42 | 49 | 51 | 52 | 54 | 53 | 47 | 38 | 38 | 34 | 32 | 44 |
| Wind speed, km/h | 12 | 12 | 12 | 9 | 9 | 8 | 7 | 7 | 7 | 8 | 8 | 10 | 9 |
| Day Length, часов | 12 | 13 | 14 | 14 | 14 | 13 | 13 | 13 | 11 | 11 | 11 | 12 | 13 |
| Dew point, °C | 5 | 9 | 12 | 14 | 14 | 14 | 13 | 10 | 5 | 1 | 1 | 2 | 100 |
| Growing degree-day, °C | 195 | 260 | 288 | 329 | 344 | 302 | 295 | 198 | 109 | 9 | 16 | 99 | 2443 |
| Solar radiation, global, Mj/m2 | 22 | 22 | 23 | 24 | 24 | 23 | 21 | 18 | 17 | 15 | 16 | 19 | 20 |