Last spring frost
Mar 24
Frost Dates for Cromwell, OK
First fall frost
Nov 9
Growing season
229 days
Hardiness zone
7b
In an average year around Cromwell, OK, the last spring frost (32°F) is about Mar 24 and the first fall frost is about Nov 9, giving roughly a 229-day growing season. To be safe most years, wait until Mar 5 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Apr 22 | Apr 5 | Mar 19 |
| Freeze (32°F) | Apr 10 | Mar 24 | Mar 5 |
| Hard (28°F) | Mar 29 | Mar 11 | Feb 23 |
| Severe (24°F) | Mar 17 | Mar 1 | Feb 10 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 22 | Apr 17 | Apr 12 | Apr 8 | Apr 5 | Apr 2 | Mar 30 | Mar 26 | Mar 19 |
| 32°F | Apr 10 | Apr 4 | Mar 31 | Mar 28 | Mar 24 | Mar 20 | Mar 16 | Mar 12 | Mar 5 |
| 28°F | Mar 29 | Mar 23 | Mar 18 | Mar 15 | Mar 11 | Mar 8 | Mar 4 | Feb 28 | Feb 23 |
| 24°F | Mar 17 | Mar 11 | Mar 8 | Mar 4 | Mar 1 | Feb 26 | Feb 22 | Feb 18 | Feb 10 |
| 20°F | Mar 10 | Mar 5 | Feb 28 | Feb 24 | Feb 19 | Feb 14 | Feb 9 | Feb 2 | Jan 25 |
| 16°F | Mar 4 | Feb 25 | Feb 18 | Feb 12 | Feb 5 | Jan 31 | Jan 25 | Jan 17 | Jan 5 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Oct 16 | Nov 1 | Nov 14 |
| Freeze (32°F) | Oct 25 | Nov 9 | Nov 26 |
| Hard (28°F) | Nov 2 | Nov 20 | Dec 8 |
| Severe (24°F) | Nov 13 | Dec 2 | Dec 22 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 16 | Oct 21 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 5 | Nov 8 | Nov 14 |
| 32°F | Oct 25 | Oct 31 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 16 | Nov 20 | Nov 26 |
| 28°F | Nov 2 | Nov 8 | Nov 12 | Nov 17 | Nov 20 | Nov 24 | Nov 27 | Dec 2 | Dec 8 |
| 24°F | Nov 13 | Nov 20 | Nov 24 | Nov 28 | Dec 2 | Dec 5 | Dec 10 | Dec 15 | Dec 22 |
| 20°F | Nov 24 | Dec 1 | Dec 5 | Dec 10 | Dec 15 | Dec 21 | Dec 28 | Jan 3 | Jan 12 |
| 16°F | Dec 4 | Dec 11 | Dec 17 | Dec 24 | Dec 31 | Jan 4 | Jan 9 | Jan 16 | Feb 2 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Okemah, Ok, about 10.3 miles away@if(!empty($station['elevation_ft'])), at 935 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Cromwell, OK?
On average, the last spring frost (32°F) around Cromwell, OK is about Mar 24. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 5.
When is the first frost in the fall?
The first fall frost around Cromwell, OK typically arrives about Nov 9. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Mar 24 on average, or Mar 5 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 229 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 74837 Planting calendar → Oklahoma frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026