Frost dates and when to plant in Oklahoma

United States

In Oklahoma the last spring frost comes between 1 March (Lawton) and 14 March (Oklahoma City) — the median of 2016–2025 in 3 cities. The first autumn frost comes between 10 November (Oklahoma City) and 17 November (Tulsa). The frost-free season lasts 241–256 days. Tomato: plant out into open ground 13 March – 28 July, earliest in Lawton, latest in Tulsa.

Frost dates by city in Oklahoma

City	Last spring frost	First autumn frost	Frost-free days	Climate zone	Tomato: window
Lawton	1 March	11 November	255	210–269 frost-free days	13 March – 22 July
Tulsa	6 March	17 November	256	210–269 frost-free days	6 April – 28 July
Oklahoma City	14 March	10 November	241	210–269 frost-free days	23 March – 21 July

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 plant in Oklahoma: windows by crop

The earliest start and the latest end among the cities here, each with its city; every city’s own window is on its page. 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.

Crop	Planting out or sowing
Tomato	13 March (Lawton) – 28 July (Tulsa)
Cucumber	4 April (Lawton) – 2 September (Tulsa)
Bell Pepper, Eggplant	4 April (Lawton) – 28 July (Tulsa)
Zucchini	4 April (Lawton) – 31 August (Tulsa)
Pumpkin	4 April (Lawton) – 23 July (Tulsa)
Watermelon	4 April (Lawton) – 8 August (Tulsa)
Peas	8 February (Lawton) – 4 September (Tulsa)
Garlic	Autumn planting: 11 October (Oklahoma City) – end of December (Oklahoma City)
Tulip, Daffodil, Crocus, Hyacinth	Autumn planting: by 11 October (Oklahoma City)

Weather by month in Oklahoma

Across the 3 cities the warmest month is July (average days 33.6 … 35.8 °C) and the coldest January (average nights -0.9 … 0.2 °C). 2 of the 3 cities have months with nights below 0 °C on average; the longest such winter is in Oklahoma City (January).

Month	Day, °C	Night, °C	Rain, mm
January	8.7 … 11.8 °C	-0.9 … 0.2 °C	41
February	12.2 … 14.9 °C	1 … 2 °C	47
March	18.5 … 21 °C	7 … 8 °C	70
April	21.9 … 24.5 °C	10.7 … 11.7 °C	136
May	26.1 … 28.4 °C	16 … 17.2 °C	128
June	31.7 … 33 °C	21.4 … 22.2 °C	93
July	33.6 … 35.8 °C	23.6 … 24.7 °C	68
August	32.6 … 35.5 °C	22.8 … 24.6 °C	70
September	29.9 … 31.5 °C	19.7 … 20.6 °C	87
October	23.4 … 25.6 °C	13.1 … 14 °C	85
November	16.4 … 18.6 °C	6.6 … 7.3 °C	50
December	11.8 … 14.2 °C	2.3 … 3.1 °C	35

Day and night: the lowest … highest monthly average among the cities; rain: the middle city (ERA5 via Open-Meteo).

Frost dates and when to plant in Oklahoma

Frost dates by city in Oklahoma

When to plant in Oklahoma: windows by crop

Weather by month in Oklahoma

What to plant month by month: the South

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