GreenlyJohannesburg: frost dates
South Africa
In Johannesburg the last spring frost usually comes around 4 August and the first autumn frost around 5 June, which leaves about 305 frost-free days (median of 2016–2025). Tomato seedlings can go into open ground around 21 August.
| Last spring frost | around 4 August |
|---|---|
| First autumn frost | around 5 June |
| Frost-free days | 305 days |
Median of 2016–2025 for the 25 km grid cell of the city: the last day at or below 0 °C in spring and the first in autumn (ERA5 reanalysis via Open-Meteo). In a cold year a frost can come a week or two later — Greenly warns 48 hours ahead.
When to sow and plant
| Crop | Sow for seedlings | Plant out in a greenhouse | Open ground |
|---|---|---|---|
| Bell Pepper | 3 June | 16 August | 6 September |
| Chili Pepper | 11 June | 24 August | 14 September |
| Corn | — | 21 July | sow 11 August |
| Cucumber | 5 July | 16 August | 6 September |
| Eggplant | 7 June | 16 August | 6 September |
| Green Beans | 14 June | 21 July | 11 August |
| Melon | 25 June | 16 August | 6 September |
| Peas | — | 23 June | sow 14 July |
| Physalis | 16 June | 31 July | 21 August |
| Pumpkin | 24 June | 31 July | 21 August |
| Sweet Corn | — | 21 July | sow 11 August |
| Tomato | 4 June | 31 July | 21 August |
| Watermelon | 15 July | 16 August | 6 September |
| Zucchini | 29 June | 31 July | 21 August |
Planting out: a week after the last frost once the soil is warm enough for the crop; frost-hardy crops three weeks before it; an unheated greenhouse three weeks earlier. Seedlings are sown so they are ready on that day.
Johannesburg: weather for the next 7 days
Forecast by Open-Meteo. Nights at or below 0 °C are marked as frost.
Planted in autumn
A month before the first autumn frost, so the roots grow before winter.