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Last and first frost dates in Southampton

United Kingdom

In Southampton the last spring frost usually comes around 4 April and the first autumn frost around 23 November, which leaves about 233 frost-free days (median of 2016–2025). Tomato seedlings can go into open ground from 23 May to 3 August.

Last spring frostaround 4 April
First autumn frostaround 23 November
Frost-free days233 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 is the last frost in Southampton?

The last frost in Southampton usually comes around 4 April: that is the median of 2016–2025, so in about half of those years the last night at or below 0 °C came later. Hardy crops start before it and frost-tender ones only after it: in the table below arugula can go into open ground from 14 March, while corn waits until 5 May. The first autumn frost follows around 23 November, about 233 days later: harvest or cover frost-tender crops before then.

When to sow and plant

CropSow for seedlingsPlant out in a greenhouseOpen ground
Achocha14 February – 15 August26 March – 24 September16 April – 24 September
Ageratumfrom 7 March—from 23 May
Arugula——sow 14 March – 19 October
Basil19 April – 21 September27 May – 29 October17 June – 29 October
Beet——sow 14 March – 24 September
Bell Pepper28 March – 4 June27 May – 3 August17 June – 3 August
Black-eyed Susanfrom 23 January—from 16 April
Bok Choy19 February – 2 October26 March – 6 November16 April – 6 November
Borage——sow 11 April – 29 September
Broad bean——sow 14 March – 15 August
Broccoli——sow 14 March – 8 August
Brussels Sprouts7 January – 6 July21 February – 20 August14 March – 20 August
Busy Lizziefrom 17 January—from 11 April
Cabbage——sow 14 March – 16 July
Calendula——sow from 14 March
Carrot——sow 14 March – 31 August
Cauliflower10 January – 8 August21 February – 19 September14 March – 19 September
Celeriac8 January – 5 June26 March – 21 August16 April – 21 August
Celery8 January – 15 June26 March – 31 August16 April – 31 August
Celosiafrom 31 Marchfrom 15 Mayfrom 5 June
Chamomile——sow 14 March – 19 September
Chayote16 January – 29 May14 April – 25 August5 May – 25 August
Chickpea——sow 14 March – 5 August
Chicory27 January – 30 August—14 March – 24 September
Chili Pepper28 March – 11 July27 May – 9 September17 June – 9 September
China asterfrom 5 Aprilfrom 27 Mayfrom 17 June
Chives——sow 14 March – 10 September
Cilantro——sow 14 March – 20 September
Corn——sow 5 May – 5 August
Corn poppy——sow from 14 March
Cosmosfrom 31 Marchfrom 15 Mayfrom 5 June
Cucumber29 April – 11 August27 May – 8 September17 June – 8 September
Daikon——sow 14 March – 17 September
Delphiniumfrom 24 December—from 14 March
Dill——sow 14 March – 30 September
Edging lobeliafrom 22 January—from 16 April
Eggplant28 March – 4 June27 May – 3 August17 June – 3 August
Florence fennel9 February – 15 August26 March – 29 September16 April – 29 September
Foxglovefrom 6 December—from 14 March
Garden sorrel——sow 14 March – 18 September
Green Beans——sow 5 June – 13 August
Hollyhock——sow from 14 March
Hyssop——sow 14 March – 11 August
Kale——sow 14 March – 12 September
Kiwano31 March – 18 August2 May – 19 September23 May – 19 September
Kohlrabi——sow 14 March – 22 September
Leek13 December – 27 May21 February – 5 August14 March – 5 August
Lemon balm——sow 14 March – 14 September
Lettuce——sow 14 March – 27 September
Lisianthusfrom 26 Novemberfrom 21 Februaryfrom 14 March
Lovage——sow from 14 March
Luffa15 April – 12 June27 May – 24 July17 June – 24 July
Marigoldfrom 12 Februaryfrom 26 Marchfrom 16 April
Marjoram28 March – 30 August—17 June – 29 October
Melon29 April – 29 July27 May – 26 August17 June – 26 August
Microgreens——sow 5 June – 9 November
Moringa10 April – 4 September4 June – 29 October25 June – 29 October
Moss rosefrom 24 January—from 11 April
Mustard greens——sow 14 March – 9 October
Napa cabbage21 February – 9 September26 March – 12 October16 April – 12 October
Nasturtiumfrom 16 Februaryfrom 26 Marchfrom 16 April
Okra15 April – 23 August27 May – 4 October17 June – 4 October
Oregano23 December – 20 August21 February – 19 October14 March – 19 October
Pansyfrom 27 Decemberfrom 21 Februaryfrom 14 March
Parsley——sow 14 March – 8 September
Parsnip——sow 14 March – 28 July
Peanut20 April – 19 July27 May – 25 August17 June – 25 August
Peas——sow 14 March – 10 September
Petuniafrom 25 Marchfrom 27 Mayfrom 17 June
Physalis18 March – 16 July2 May – 30 August23 May – 30 August
Pumpkin15 April – 17 June27 May – 29 July17 June – 29 July
Purple coneflowerfrom 21 December—from 14 March
Radish——sow 14 March – 24 October
Sage3 January – 16 August21 February – 4 October14 March – 4 October
Scarlet sagefrom 11 March—from 23 May
Snapdragonfrom 18 Decemberfrom 21 Februaryfrom 14 March
Soybean——sow 17 June – 4 September
Spinach——sow 14 March – 29 September
Stevia14 March – 7 July2 May – 25 August23 May – 25 August
Stock——sow from 14 March
Sunflower——sow from 5 June
Sweet alyssum——sow from 14 March
Sweet Corn27 March – 30 August18 April – 21 September9 May – 21 September
Sweet peafrom 10 Januaryfrom 21 Februaryfrom 14 March
Sweet William——sow from 14 March
Swiss Chard——sow 14 March – 24 September
Thyme——sow 14 March – 5 August
Tomato11 March – 12 June2 May – 3 August23 May – 3 August
Turnip——sow 14 March – 26 September
Watercress——sow 14 March – 7 October
Watermelon29 April – 17 July27 May – 14 August17 June – 14 August
Zinniafrom 30 Aprilfrom 4 Junefrom 25 June
Zucchini6 May – 16 August27 May – 6 September17 June – 6 September

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. Each window starts on the Greenly calendar date and ends on the last day that still leaves the crop’s days to harvest (from its card) before the average first autumn frost, plus six weeks of picking for crops harvested over weeks (tomatoes, peppers, aubergines, cucumbers, courgettes, pumpkins, watermelons, beans) — our rule; earlier in the window is safer.

When the soil warms up in Southampton

The day the top 7 cm of soil first averages each temperature over a week, median of 2016–2025 (ERA5 via Open-Meteo). The soil reaches 10 °C 12 days after the last spring frost and 15 °C 49 days after it.

SoilDateAgainst the last spring frost
5 °Calready in the first week of January—
10 °C16 April12 days later
15 °C23 May49 days later
18 °C17 June74 days later

Frost dates near Southampton

Of the nearest cities on our list, the last spring frost ends earliest in Brighton (8 February) and latest in Bristol (11 April).

CityDistanceLast spring frostFirst autumn frost
Portsmouth24 km4 March1 December
Brighton89 km8 February1 December
Oxford95 km3 April23 November
Bristol103 km11 April22 November
London111 km4 April23 November

Seeds, seedlings and markets in Southampton

Within 15 km of Southampton OpenStreetMap lists 28 garden centres, 15 plant nurseries, 1 market and 10 farm shops (collected 20 October 2026). The nearest garden centre to the city centre is Greenhouse People, 5 km away.

Places: © OpenStreetMap contributors, ODbL.

What to grow at home in winter in Southampton

Frosts in Southampton usually come from about 23 November to about 4 April. These plants have indoor care in their Greenly cards and are harvested quickly, so they can be sown on a windowsill in winter.

Weather in Southampton by month

Average weather in Southampton over 2016–2025: the warmest month is July. Months that average 20 °C or more by day: June (20.5 °C), July (22.3 °C) and August (21.8 °C). No month averages below 0 °C at night; the coldest nights, in January, average 1.9 °C. About 852 mm of rain falls in a year, on 138 days; October is the wettest month (100 mm) and April the driest (49 mm).

MonthDay, °CNight, °CRain, mmRainy days
January7.91.97612
February9.32.96912
March113.87313
April13.84.9499
May17.48.26211
June20.511.55911
July22.313.55410
August21.813.36010
September19.211.27311
October15.48.810013
November11.15.28613
December9.34.19113

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

CropWhen to plant
Bearded Irisby 24 October
Crocus24 October – end of December
Daffodil24 October – end of December
Garlic24 October – end of December
Grape hyacinthby 24 October
Helleboreby 24 October
Hyacinth24 October – end of December
Lilyby 24 October
Ornamental onionby 24 October
Peonyby 24 October
Saffronby 24 October
Snowdropby 24 October
Tulip24 October – end of December
Wild garlicby 24 October

From a month before the first autumn frost, so the roots grow before winter, to the late-planting limit on each crop’s page (about two weeks before the ground freezes, by ten years of weather).