GreenlySumy: frost dates
Ukraine
In Sumy the last spring frost usually comes around 22 April and the first autumn frost around 20 October, which leaves about 181 frost-free days (median of 2016–2025). Tomato seedlings can go into open ground around 15 May.
| Last spring frost | around 22 April |
|---|---|
| First autumn frost | around 20 October |
| Frost-free days | 181 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 |
|---|---|---|---|
| Achocha | 27 February | 8 April | 29 April |
| Arugula | — | 11 March | sow 1 April |
| Basil | 31 March | 8 May | 29 May |
| Beet | — | 11 March | sow 1 April |
| Bell Pepper | 23 February | 8 May | 29 May |
| Black-eyed Susan | 26 February | — | 29 April |
| Bok Choy | 4 March | 8 April | 29 April |
| Broad bean | — | 11 March | sow 1 April |
| Broccoli | — | 11 March | sow 1 April |
| Brussels Sprouts | 25 January | 11 March | 1 April |
| Cabbage | — | 11 March | sow 1 April |
| Calendula | — | 11 March | sow 1 April |
| Carrot | — | — | sow 1 April |
| Cauliflower | 28 January | 11 March | 1 April |
| Celeriac | 21 January | 8 April | 29 April |
| Celery | 21 January | 8 April | 29 April |
| Celosia | 20 March | 4 May | 25 May |
| Chamomile | — | 11 March | sow 1 April |
| Chayote | 12 January | 10 April | 1 May |
| Chickpea | — | — | sow 1 April |
| Chili Pepper | 12 March | 25 May | 15 June |
| China aster | 17 March | 8 May | 29 May |
| Chives | — | — | sow 1 April |
| Cilantro | — | 11 March | sow 1 April |
| Corn | — | 10 April | sow 1 May |
| Cosmos | 20 March | 4 May | 25 May |
| Cucumber | 27 March | 8 May | 29 May |
| Daikon | — | 11 March | sow 1 April |
| Delphinium | 1 February | — | 1 April |
| Dill | — | 11 March | sow 1 April |
| Eggplant | 27 February | 8 May | 29 May |
| Florence fennel | 22 February | 8 April | 29 April |
| Garden sorrel | — | 11 March | sow 1 April |
| Green Beans | 4 March | 10 April | 1 May |
| Hyssop | — | — | sow 1 April |
| Kale | — | 11 March | sow 1 April |
| Kiwano | 23 March | 24 April | 15 May |
| Kohlrabi | — | 11 March | sow 1 April |
| Leek | 31 December | 11 March | 1 April |
| Lemon balm | — | 11 March | sow 1 April |
| Lettuce | — | 11 March | sow 1 April |
| Lisianthus | 14 December | 11 March | 1 April |
| Lovage | — | — | sow 1 April |
| Luffa | 27 March | 8 May | 29 May |
| Marigold | 25 February | 8 April | 29 April |
| Melon | 17 March | 8 May | 29 May |
| Microgreens | — | 4 May | sow 25 May |
| Moringa | 31 March | 25 May | 15 June |
| Mustard greens | — | 11 March | sow 1 April |
| Napa cabbage | 6 March | 8 April | 29 April |
| Nasturtium | 1 March | 8 April | 29 April |
| Okra | 27 March | 8 May | 29 May |
| Oregano | 10 January | 11 March | 1 April |
| Pansy | 14 January | 11 March | 1 April |
| Parsley | — | 11 March | sow 1 April |
| Parsnip | — | — | sow 1 April |
| Peanut | 1 April | 8 May | 29 May |
| Peas | — | 11 March | sow 1 April |
| Petunia | 6 March | 8 May | 29 May |
| Physalis | 10 March | 24 April | 15 May |
| Pumpkin | 18 March | 24 April | 15 May |
| Purple coneflower | 29 January | — | 1 April |
| Radish | — | — | sow 1 April |
| Sage | 21 January | 11 March | 1 April |
| Snapdragon | 5 January | 11 March | 1 April |
| Spinach | — | 11 March | sow 1 April |
| Stevia | 6 March | 24 April | 15 May |
| Stock | — | 11 March | sow 1 April |
| Sunflower | — | 4 May | sow 25 May |
| Sweet Corn | — | 10 April | sow 1 May |
| Sweet pea | 28 January | 11 March | 1 April |
| Sweet William | — | — | sow 1 April |
| Swiss Chard | — | 11 March | sow 1 April |
| Thyme | — | 11 March | sow 1 April |
| Tomato | 26 February | 24 April | 15 May |
| Turnip | — | 11 March | sow 1 April |
| Watercress | — | 11 March | sow 1 April |
| Watermelon | 6 April | 8 May | 29 May |
| Zinnia | 20 April | 25 May | 15 June |
| Zucchini | 23 March | 24 April | 15 May |
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.
Sumy: weather for the next 7 days
Forecast by Open-Meteo. Nights at or below 0 °C are marked as frost.
Weather in Sumy by month
Average weather in Sumy over 2016–2025: the warmest month is August, the wettest June.
| Month | Day, °C | Night, °C | Rain, mm | Rainy days |
|---|---|---|---|---|
| January | -1.6 | -6.7 | 54 | 11 |
| February | -0.2 | -6.2 | 41 | 9 |
| March | 6.6 | -2 | 41 | 9 |
| April | 14.4 | 4.1 | 51 | 10 |
| May | 19.4 | 9 | 66 | 12 |
| June | 24.4 | 14.4 | 71 | 11 |
| July | 25.8 | 15.9 | 71 | 11 |
| August | 26 | 15.5 | 45 | 6 |
| September | 20.1 | 10.5 | 34 | 6 |
| October | 12.8 | 5.2 | 61 | 10 |
| November | 5 | -0.1 | 55 | 9 |
| December | 0.5 | -3.7 | 64 | 14 |
Average of the daily highs and lows, rain per month and days with at least 1 mm (ERA5 via Open-Meteo, the same grid cell as the frost dates).
Planted in autumn
| Crop | Plant around |
|---|---|
| Bearded Iris | 20 September |
| Crocus | 20 September |
| Daffodil | 20 September |
| Garlic | 20 September |
| Hyacinth | 20 September |
| Lily | 20 September |
| Peony | 20 September |
| Saffron | 20 September |
| Tulip | 20 September |
| Wild garlic | 20 September |
A month before the first autumn frost, so the roots grow before winter.