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Last and first frost dates in Fort Smith

United States

In Fort Smith the last spring frost usually comes around 16 March and the first autumn frost around 18 November, which leaves about 247 frost-free days (median of 2016–2025). Tomato seedlings can go into open ground from 5 April to 29 July.

Last spring frostaround 16 March
First autumn frostaround 18 November
Frost-free days247 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 Fort Smith?

The last frost in Fort Smith usually comes around 16 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 23 February, while corn waits until 23 March. The first autumn frost follows around 18 November, about 247 days later: harvest or cover frost-tender crops before then.

When to sow and plant

CropSow for seedlingsPlant out in a greenhouseOpen ground
Achocha21 January – 10 August2 March – 19 September23 March – 19 September
Ageratumfrom 18 January—from 5 April
Arugula——sow 23 February – 14 October
Basil3 March – 16 September10 April – 24 October1 May – 24 October
Beet——sow 23 February – 19 September
Bell Pepper9 February – 30 May10 April – 29 July1 May – 29 July
Black-eyed Susanfrom 30 December—from 23 March
Bok Choy26 January – 27 September2 March – 1 November23 March – 1 November
Borage——sow 23 March – 24 September
Broad bean——sow 23 February – 10 August
Broccoli——sow 23 February – 3 August
Brussels Sprouts19 December – 1 July2 February – 15 August23 February – 15 August
Busy Lizziefrom 29 December—from 23 March
Cabbage——sow 23 February – 11 July
Calendula——sow from 23 February
Carrot——sow 23 February – 26 August
Cauliflower22 December – 3 August2 February – 14 September23 February – 14 September
Celeriac15 December – 31 May2 March – 16 August23 March – 16 August
Celery15 December – 10 June2 March – 26 August23 March – 26 August
Celosiafrom 4 Februaryfrom 21 Marchfrom 11 April
Chamomile——sow 23 February – 14 September
Chayote4 December – 24 May2 March – 20 August23 March – 20 August
Chickpea——sow 23 February – 31 July
Chicory8 January – 25 August—23 February – 19 September
Chili Pepper9 February – 6 July10 April – 4 September1 May – 4 September
China asterfrom 17 Februaryfrom 10 Aprilfrom 1 May
Chives——sow 23 February – 5 September
Cilantro——sow 23 February – 15 September
Corn——sow 23 March – 31 July
Corn poppy——sow from 23 February
Cosmosfrom 4 Februaryfrom 21 Marchfrom 11 April
Cucumber13 March – 6 August10 April – 3 September1 May – 3 September
Daikon——sow 23 February – 12 September
Delphiniumfrom 5 December—from 23 February
Dill——sow 23 February – 25 September
Edging lobeliafrom 29 December—from 23 March
Eggplant9 February – 30 May10 April – 29 July1 May – 29 July
Florence fennel16 January – 10 August2 March – 24 September23 March – 24 September
Foxglovefrom 17 November—from 23 February
Garden sorrel——sow 23 February – 13 September
Green Beans——sow 11 April – 8 August
Hollyhock——sow from 23 February
Hyssop——sow 23 February – 6 August
Kale——sow 23 February – 7 September
Kiwano11 February – 13 August15 March – 14 September5 April – 14 September
Kohlrabi——sow 23 February – 17 September
Leek24 November – 22 May2 February – 31 July23 February – 31 July
Lemon balm——sow 23 February – 9 September
Lettuce——sow 23 February – 22 September
Lisianthusfrom 7 Novemberfrom 2 Februaryfrom 23 February
Lovage——sow from 23 February
Luffa27 February – 7 June10 April – 19 July1 May – 19 July
Marigoldfrom 19 Januaryfrom 2 Marchfrom 23 March
Marjoram9 February – 25 August—1 May – 24 October
Melon13 March – 24 July10 April – 21 August1 May – 21 August
Microgreens——sow 11 April – 4 November
Moringa28 February – 30 August24 April – 24 October15 May – 24 October
Moss rosefrom 5 January—from 23 March
Mustard greens——sow 23 February – 4 October
Napa cabbage28 January – 4 September2 March – 7 October23 March – 7 October
Nasturtiumfrom 23 Januaryfrom 2 Marchfrom 23 March
Okra27 February – 18 August10 April – 29 September1 May – 29 September
Oregano4 December – 15 August2 February – 14 October23 February – 14 October
Pansyfrom 8 Decemberfrom 2 Februaryfrom 23 February
Parsley——sow 23 February – 3 September
Parsnip——sow 23 February – 23 July
Peanut4 March – 14 July10 April – 20 August1 May – 20 August
Peas——sow 23 February – 5 September
Petuniafrom 6 Februaryfrom 10 Aprilfrom 1 May
Physalis29 January – 11 July15 March – 25 August5 April – 25 August
Pumpkin27 February – 12 June10 April – 24 July1 May – 24 July
Purple coneflowerfrom 2 December—from 23 February
Radish——sow 23 February – 19 October
Sage15 December – 11 August2 February – 29 September23 February – 29 September
Scarlet sagefrom 22 January—from 5 April
Snapdragonfrom 29 Novemberfrom 2 Februaryfrom 23 February
Soybean——sow 1 May – 30 August
Spinach——sow 23 February – 24 September
Stevia25 January – 2 July15 March – 20 August5 April – 20 August
Stock——sow from 23 February
Sunflower——sow from 11 April
Sweet alyssum——sow from 23 February
Sweet Corn8 February – 25 August2 March – 16 September23 March – 16 September
Sweet peafrom 22 Decemberfrom 2 Februaryfrom 23 February
Sweet William——sow from 23 February
Swiss Chard——sow 23 February – 19 September
Thyme——sow 23 February – 31 July
Tomato22 January – 7 June15 March – 29 July5 April – 29 July
Turnip——sow 23 February – 21 September
Watercress——sow 23 February – 2 October
Watermelon13 March – 12 July10 April – 9 August1 May – 9 August
Zinniafrom 20 Marchfrom 24 Aprilfrom 15 May
Zucchini20 March – 11 August10 April – 1 September1 May – 1 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 Fort Smith

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 28 days before the last spring frost and 15 °C 20 days after it.

SoilDateAgainst the last spring frost
5 °C17 January58 days earlier
10 °C16 February28 days earlier
15 °C5 April20 days later
18 °C1 May46 days later

Frost dates near Fort Smith

Of the nearest cities on our list, the last spring frost ends earliest in Little Rock (3 March) and latest in Joplin (30 March).

CityDistanceLast spring frostFirst autumn frost
Fayetteville78 km30 March10 November
Tulsa169 km6 March17 November
Joplin189 km30 March1 November
Little Rock203 km3 March20 November
Oklahoma City285 km14 March10 November

What to grow at home in winter in Fort Smith

Frosts in Fort Smith usually come from about 18 November to about 16 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 Fort Smith by month

Average weather in Fort Smith over 2016–2025: the warmest month is July. Months that average 20 °C or more by day: April–October (22–33.5 °C). Months that average 30 °C or more by day: June–September (30.3–33.5 °C). Nights average below 0 °C in January (-0.2 °C). About 1285 mm of rain falls in a year, on 114 days; April is the wettest month (175 mm) and September the driest (73 mm).

MonthDay, °CNight, °CRain, mmRainy days
January9.7-0.2888
February13.52.2909
March18.87.214112
April2210.717512
May26.315.915113
June31.520.89511
July33.523.29110
August32.622.4889
September30.319.4736
October2413.21138
November17.16.5918
December12.53.1898

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 19 October
Crocusby 19 October
Daffodilby 19 October
Garlic19 October – end of December
Grape hyacinthby 19 October
Helleboreby 19 October
Hyacinthby 19 October
Lilyby 19 October
Ornamental onionby 19 October
Peonyby 19 October
Saffronby 19 October
Snowdropby 19 October
Tulipby 19 October
Wild garlicby 19 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).