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Last and first frost dates in Basel

Switzerland

In Basel the last spring frost usually comes around 5 April and the first autumn frost around 20 November, which leaves about 229 frost-free days (median of 2016–2025). Tomato seedlings can go into open ground from 14 May to 31 July.

Last spring frostaround 5 April
First autumn frostaround 20 November
Frost-free days229 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 Basel?

The last frost in Basel usually comes around 5 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 15 March, while corn waits until 20 April. The first autumn frost follows around 20 November, about 229 days later: harvest or cover frost-tender crops before then.

When to sow and plant

CropSow for seedlingsPlant out in a greenhouseOpen ground
Achocha10 February – 12 August22 March – 21 September12 April – 21 September
Ageratumfrom 26 February—from 14 May
Arugula——sow 15 March – 16 October
Basil7 April – 18 September15 May – 26 October5 June – 26 October
Beet——sow 15 March – 21 September
Bell Pepper16 March – 1 June15 May – 31 July5 June – 31 July
Black-eyed Susanfrom 19 January—from 12 April
Bok Choy15 February – 29 September22 March – 3 November12 April – 3 November
Borage——sow 12 April – 26 September
Broad bean——sow 15 March – 12 August
Broccoli——sow 15 March – 5 August
Brussels Sprouts8 January – 3 July22 February – 17 August15 March – 17 August
Busy Lizziefrom 18 January—from 12 April
Cabbage——sow 15 March – 13 July
Calendula——sow from 15 March
Carrot——sow 15 March – 28 August
Cauliflower11 January – 5 August22 February – 16 September15 March – 16 September
Celeriac4 January – 2 June22 March – 18 August12 April – 18 August
Celery4 January – 12 June22 March – 28 August12 April – 28 August
Celosiafrom 25 Marchfrom 9 Mayfrom 30 May
Chamomile——sow 15 March – 16 September
Chayote1 January – 26 May30 March – 22 August20 April – 22 August
Chickpea——sow 15 March – 2 August
Chicory28 January – 27 August—15 March – 21 September
Chili Pepper16 March – 8 July15 May – 6 September5 June – 6 September
China asterfrom 24 Marchfrom 15 Mayfrom 5 June
Chives——sow 15 March – 7 September
Cilantro——sow 15 March – 17 September
Corn——sow 20 April – 2 August
Corn poppy——sow from 15 March
Cosmosfrom 25 Marchfrom 9 Mayfrom 30 May
Cucumber17 April – 8 August15 May – 5 September5 June – 5 September
Daikon——sow 15 March – 14 September
Delphiniumfrom 25 December—from 15 March
Dill——sow 15 March – 27 September
Edging lobeliafrom 18 January—from 12 April
Eggplant16 March – 1 June15 May – 31 July5 June – 31 July
Florence fennel5 February – 12 August22 March – 26 September12 April – 26 September
Foxglovefrom 7 December—from 15 March
Garden sorrel——sow 15 March – 15 September
Green Beans——sow 30 May – 10 August
Hollyhock——sow from 15 March
Hyssop——sow 15 March – 8 August
Kale——sow 15 March – 9 September
Kiwano22 March – 15 August23 April – 16 September14 May – 16 September
Kohlrabi——sow 15 March – 19 September
Leek14 December – 24 May22 February – 2 August15 March – 2 August
Lemon balm——sow 15 March – 11 September
Lettuce——sow 15 March – 24 September
Lisianthusfrom 27 Novemberfrom 22 Februaryfrom 15 March
Lovage——sow from 15 March
Luffa3 April – 9 June15 May – 21 July5 June – 21 July
Marigoldfrom 8 Februaryfrom 22 Marchfrom 12 April
Marjoram16 March – 27 August—5 June – 26 October
Melon17 April – 26 July15 May – 23 August5 June – 23 August
Microgreens——sow 30 May – 6 November
Moringa1 April – 1 September26 May – 26 October16 June – 26 October
Moss rosefrom 25 January—from 12 April
Mustard greens——sow 15 March – 6 October
Napa cabbage17 February – 6 September22 March – 9 October12 April – 9 October
Nasturtiumfrom 12 Februaryfrom 22 Marchfrom 12 April
Okra3 April – 20 August15 May – 1 October5 June – 1 October
Oregano24 December – 17 August22 February – 16 October15 March – 16 October
Pansyfrom 28 Decemberfrom 22 Februaryfrom 15 March
Parsley——sow 15 March – 5 September
Parsnip——sow 15 March – 25 July
Peanut8 April – 16 July15 May – 22 August5 June – 22 August
Peas——sow 15 March – 7 September
Petuniafrom 13 Marchfrom 15 Mayfrom 5 June
Physalis9 March – 13 July23 April – 27 August14 May – 27 August
Pumpkin3 April – 14 June15 May – 26 July5 June – 26 July
Purple coneflowerfrom 22 December—from 15 March
Radish——sow 15 March – 21 October
Sage4 January – 13 August22 February – 1 October15 March – 1 October
Scarlet sagefrom 2 March—from 14 May
Snapdragonfrom 19 Decemberfrom 22 Februaryfrom 15 March
Soybean——sow 5 June – 1 September
Spinach——sow 15 March – 26 September
Stevia5 March – 4 July23 April – 22 August14 May – 22 August
Stock——sow from 15 March
Sunflower——sow from 30 May
Sweet alyssum——sow from 15 March
Sweet Corn20 March – 27 August11 April – 18 September2 May – 18 September
Sweet peafrom 11 Januaryfrom 22 Februaryfrom 15 March
Sweet William——sow from 15 March
Swiss Chard——sow 15 March – 21 September
Thyme——sow 15 March – 2 August
Tomato2 March – 9 June23 April – 31 July14 May – 31 July
Turnip——sow 15 March – 23 September
Watercress——sow 15 March – 4 October
Watermelon17 April – 14 July15 May – 11 August5 June – 11 August
Zinniafrom 21 Aprilfrom 26 Mayfrom 16 June
Zucchini24 April – 13 August15 May – 3 September5 June – 3 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 Basel

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 5 days before the last spring frost and 15 °C 39 days after it.

SoilDateAgainst the last spring frost
5 °C22 January73 days earlier
10 °C31 March5 days earlier
15 °C14 May39 days later
18 °C5 June61 days later

Frost dates near Basel

Of the nearest cities on our list, the last spring frost ends earliest in Mulhouse (6 April) and latest in Biel/Bienne (29 April).

CityDistanceLast spring frostFirst autumn frost
Mulhouse29 km6 April17 November
Freiburg im Breisgau52 km12 April16 November
Biel/Bienne53 km29 April4 November
Colmar60 km20 April17 November
Bern69 km24 April3 November

Seeds, seedlings and markets in Basel

Within 15 km of Basel OpenStreetMap lists 16 garden centres, 2 farm-supply shops, 2 plant nurseries, 18 markets and 125 farm shops (collected 27 October 2026). The nearest garden centre to the city centre is Gartenzenter Wyss, 5 km away.

Places: © OpenStreetMap contributors, ODbL.

What to grow at home in winter in Basel

Frosts in Basel usually come from about 20 November to about 5 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 Basel by month

Average weather in Basel over 2016–2025: the warmest month is August. Months that average 20 °C or more by day: June–September (21.2–25.6 °C). Nights average below 0 °C in January (-0.3 °C). About 1189 mm of rain falls in a year, on 166 days; May is the wettest month (127 mm) and February the driest (73 mm).

MonthDay, °CNight, °CRain, mmRainy days
January6-0.310515
February8.91.47312
March11.82.78014
April15.25.59412
May18.69.512717
June2414.511816
July25.415.810814
August25.615.89512
September21.212.28612
October16.68.510012
November103.510716
December71.19614

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 21 October
Crocus21 October – end of December
Daffodil21 October – end of December
Garlic21 October – end of December
Grape hyacinthby 21 October
Helleboreby 21 October
Hyacinth21 October – end of December
Lilyby 21 October
Ornamental onionby 21 October
Peonyby 21 October
Saffronby 21 October
Snowdropby 21 October
Tulip21 October – end of December
Wild garlicby 21 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).