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Last and first frost dates in Rennes

France

In Rennes the last spring frost usually comes around 12 March and the first autumn frost around 28 November, which leaves about 261 frost-free days (median of 2016–2025). Tomato seedlings can go into open ground from 13 May to 8 August.

Last spring frostaround 12 March
First autumn frostaround 28 November
Frost-free days261 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 Rennes?

The last frost in Rennes usually comes around 12 March: 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 19 February, while corn waits until 13 April. The first autumn frost follows around 28 November, about 261 days later: harvest or cover frost-tender crops before then.

When to sow and plant

CropSow for seedlingsPlant out in a greenhouseOpen ground
Achocha20 January – 20 August1 March – 29 September22 March – 29 September
Ageratumfrom 25 February—from 13 May
Arugula——sow 19 February – 24 October
Basil3 April – 26 September11 May – 3 November1 June – 3 November
Beet——sow 19 February – 29 September
Bell Pepper12 March – 9 June11 May – 8 August1 June – 8 August
Black-eyed Susanfrom 29 December—from 22 March
Bok Choy25 January – 7 October1 March – 11 November22 March – 11 November
Borage——sow 19 March – 4 October
Broad bean——sow 19 February – 20 August
Broccoli——sow 19 February – 13 August
Brussels Sprouts15 December – 11 July29 January – 25 August19 February – 25 August
Busy Lizziefrom 25 December—from 19 March
Cabbage——sow 19 February – 21 July
Calendula——sow from 19 February
Carrot——sow 19 February – 5 September
Cauliflower18 December – 13 August29 January – 24 September19 February – 24 September
Celeriac14 December – 10 June1 March – 26 August22 March – 26 August
Celery14 December – 20 June1 March – 5 September22 March – 5 September
Celosiafrom 22 Marchfrom 6 Mayfrom 27 May
Chamomile——sow 19 February – 24 September
Chayote25 December – 3 June23 March – 30 August13 April – 30 August
Chickpea——sow 19 February – 10 August
Chicory4 January – 4 September—19 February – 29 September
Chili Pepper12 March – 16 July11 May – 14 September1 June – 14 September
China asterfrom 20 Marchfrom 11 Mayfrom 1 June
Chives——sow 19 February – 15 September
Cilantro——sow 19 February – 25 September
Corn——sow 13 April – 10 August
Corn poppy——sow from 19 February
Cosmosfrom 22 Marchfrom 6 Mayfrom 27 May
Cucumber13 April – 16 August11 May – 13 September1 June – 13 September
Daikon——sow 19 February – 22 September
Delphiniumfrom 1 December—from 19 February
Dill——sow 19 February – 5 October
Edging lobeliafrom 28 December—from 22 March
Eggplant12 March – 9 June11 May – 8 August1 June – 8 August
Florence fennel15 January – 20 August1 March – 4 October22 March – 4 October
Foxglovefrom 13 November—from 19 February
Garden sorrel——sow 19 February – 23 September
Green Beans——sow 27 May – 18 August
Hollyhock——sow from 19 February
Hyssop——sow 19 February – 16 August
Kale——sow 19 February – 17 September
Kiwano21 March – 23 August22 April – 24 September13 May – 24 September
Kohlrabi——sow 19 February – 27 September
Leek20 November – 1 June29 January – 10 August19 February – 10 August
Lemon balm——sow 19 February – 19 September
Lettuce——sow 19 February – 2 October
Lisianthusfrom 3 Novemberfrom 29 Januaryfrom 19 February
Lovage——sow from 19 February
Luffa30 March – 17 June11 May – 29 July1 June – 29 July
Marigoldfrom 18 Januaryfrom 1 Marchfrom 22 March
Marjoram12 March – 4 September—1 June – 3 November
Melon13 April – 3 August11 May – 31 August1 June – 31 August
Microgreens——sow 27 May – 14 November
Moringa3 April – 9 September28 May – 3 November18 June – 3 November
Moss rosefrom 1 January—from 19 March
Mustard greens——sow 19 February – 14 October
Napa cabbage27 January – 14 September1 March – 17 October22 March – 17 October
Nasturtiumfrom 22 Januaryfrom 1 Marchfrom 22 March
Okra30 March – 28 August11 May – 9 October1 June – 9 October
Oregano30 November – 25 August29 January – 24 October19 February – 24 October
Pansyfrom 4 Decemberfrom 29 Januaryfrom 19 February
Parsley——sow 19 February – 13 September
Parsnip——sow 19 February – 2 August
Peanut4 April – 24 July11 May – 30 August1 June – 30 August
Peas——sow 19 February – 15 September
Petuniafrom 9 Marchfrom 11 Mayfrom 1 June
Physalis8 March – 21 July22 April – 4 September13 May – 4 September
Pumpkin30 March – 22 June11 May – 3 August1 June – 3 August
Purple coneflowerfrom 28 November—from 19 February
Radish——sow 19 February – 29 October
Sage11 December – 21 August29 January – 9 October19 February – 9 October
Scarlet sagefrom 1 March—from 13 May
Snapdragonfrom 25 Novemberfrom 29 Januaryfrom 19 February
Soybean——sow 1 June – 9 September
Spinach——sow 19 February – 4 October
Stevia4 March – 12 July22 April – 30 August13 May – 30 August
Stock——sow from 19 February
Sunflower——sow from 27 May
Sweet alyssum——sow from 19 February
Sweet Corn15 March – 4 September6 April – 26 September27 April – 26 September
Sweet peafrom 18 Decemberfrom 29 Januaryfrom 19 February
Sweet William——sow from 19 February
Swiss Chard——sow 19 February – 29 September
Thyme——sow 19 February – 10 August
Tomato1 March – 17 June22 April – 8 August13 May – 8 August
Turnip——sow 19 February – 1 October
Watercress——sow 19 February – 12 October
Watermelon13 April – 22 July11 May – 19 August1 June – 19 August
Zinniafrom 23 Aprilfrom 28 Mayfrom 18 June
Zucchini20 April – 21 August11 May – 11 September1 June – 11 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 Rennes

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 10 days after the last spring frost and 15 °C 62 days after it.

SoilDateAgainst the last spring frost
5 °Calready in the first week of January—
10 °C22 March10 days later
15 °C13 May62 days later
18 °C1 June81 days later

Frost dates near Rennes

Of the nearest cities on our list, the last spring frost ends earliest in Nantes (7 March) and latest in Le Mans (2 April).

CityDistanceLast spring frostFirst autumn frost
Nantes99 km7 March29 November
Angers110 km12 March27 November
Le Mans140 km2 April24 November
Caen154 km12 March5 December
Quimper180 km8 March9 December

Seeds, seedlings and markets in Rennes

Within 15 km of Rennes OpenStreetMap lists 21 garden centres, 5 farm-supply shops, 3 plant nurseries, 41 markets and 19 farm shops (collected 20 October 2026). The nearest garden centre to the city centre is Succulente Design Végétal, 0 km away.

Places: © OpenStreetMap contributors, ODbL.

What to grow at home in winter in Rennes

Frosts in Rennes usually come from about 28 November to about 12 March. 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 Rennes by month

Average weather in Rennes over 2016–2025: the warmest month is August. Months that average 20 °C or more by day: June–September (21.5–24.4 °C). No month averages below 0 °C at night; the coldest nights, in January, average 2.9 °C. About 814 mm of rain falls in a year, on 133 days; October is the wettest month (87 mm) and August the driest (48 mm).

MonthDay, °CNight, °CRain, mmRainy days
January8.82.98513
February10.53.65910
March12.74.66813
April15.76.15611
May19.19.46112
June22.812.98311
July24.314.3508
August24.414.4489
September21.512.4589
October17.49.88712
November12.46.17812
December9.94.58113

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 29 October
Crocusby 29 October
Daffodilby 29 October
Garlic29 October – end of December
Grape hyacinthby 29 October
Helleboreby 29 October
Hyacinthby 29 October
Lilyby 29 October
Ornamental onionby 29 October
Peonyby 29 October
Saffronby 29 October
Snowdropby 29 October
Tulipby 29 October
Wild garlicby 29 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).