Fort Sill, OK frost dates
Last spring frostMar 26median date
First fall frostNov 7median date
Growing season226 daysfrost-free
Hardiness zone8aZone 8a
How Fort Sill compares
- In 8 years out of 10, the last spring frost in Fort Sill falls between March 4 and April 14, a 41-day window. The first fall frost falls between October 21 and November 22.
- The median last frost is 9 days earlier than the Oklahoma median of Apr 4.
- Its 226-day growing season is longer than 88% of the 582 Oklahoma places with a regular frost season (state median 211 days).
- The last frost is typical for zone 8a, where the median is Mar 29.
- The weather station records an average of 70 nights a year at or below 32°F.
- Fort Sill shares its weather station with Lawton, OK, 5 km away, so the two have the same frost dates.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 4 |
| 50% (median) | March 26 |
| 10% (safe for tender plants) | April 14 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 21 |
| 50% (median) | November 7 |
| 90% (late) | November 22 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Fort Sill, OK
Fort Sill, OK frost dates — last frost Mar 26, first frost Nov 7, zone 8a. whenisthelastfrost.com
Crop
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Start indoors: Jan 1 to Jan 15Transplant outside: Feb 26 to Mar 12
Start indoors: Jan 15 to Jan 29Transplant outside: Apr 9 to Apr 23
Start indoors: Jan 15 to Jan 29Transplant outside: Apr 9 to Apr 23
Start indoors: Jan 29 to Feb 12Transplant outside: Apr 2 to Apr 16
Start indoors: Jan 29 to Feb 12Transplant outside: Mar 5 to Mar 19Sow outdoors: Feb 26 to Apr 2Plant for fall: Sep 12 to Oct 10
Start indoors: Jan 29 to Feb 12Transplant outside: Feb 26 to Mar 12Sow outdoors: Feb 26 to Mar 12Plant for fall: Aug 29 to Sep 19
Start indoors: Jan 29 to Feb 12Transplant outside: Mar 12 to Mar 26Plant for fall: Aug 1 to Aug 22
Start indoors: Jan 29 to Feb 12Transplant outside: Mar 5 to Mar 19Plant for fall: Aug 1 to Aug 22
Start indoors: Jan 29 to Feb 12Transplant outside: Mar 12 to Mar 26Plant for fall: Aug 1 to Aug 22
Start indoors: Feb 12 to Feb 26Transplant outside: Apr 16 to Apr 30Sow outdoors: Apr 16 to Apr 30
Start indoors: Feb 12 to Feb 26Transplant outside: Apr 2 to Apr 16
Sow outdoors: Feb 12 to Mar 5Plant for fall: Aug 15 to Sep 5
Sow outdoors: Feb 12 to Mar 5Plant for fall: Sep 12 to Oct 3
Sow outdoors: Feb 19 to Apr 2Plant for fall: Sep 26 to Oct 17
Start indoors: Feb 26 to Mar 5Transplant outside: Apr 9 to Apr 16Sow outdoors: Apr 2 to Apr 16Plant for fall: Aug 22 to Sep 5
Start indoors: Feb 26 to Mar 5Sow outdoors: Apr 2 to Apr 16Plant for fall: Aug 29 to Sep 12
Start indoors: Feb 26 to Mar 5Sow outdoors: Apr 2 to Apr 16
Start indoors: Feb 26 to Mar 5Transplant outside: Apr 9 to Apr 23
Sow outdoors: Mar 5 to Apr 2Plant for fall: Aug 15 to Aug 29
Sow outdoors: Mar 5 to Apr 2Plant for fall: Aug 29 to Sep 12
Sow outdoors: Mar 5 to Mar 26
Sow outdoors: Mar 12 to Apr 9Plant for fall: Aug 29 to Sep 12
Sow outdoors: Mar 12 to Apr 2Plant for fall: Sep 12 to Oct 3
Sow outdoors: Apr 2 to Apr 23Plant for fall: Aug 22 to Sep 5
Sow outdoors: Apr 2 to Apr 16
Transplant outside: Apr 9 to Apr 30
Plant for fall: Oct 24 to Nov 28
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Fort Sill, OK
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 1 – Jan 15 | Feb 26 – Mar 12 | — | — |
| Peppers | Jan 15 – Jan 29 | Apr 9 – Apr 23 | — | — |
| Eggplant | Jan 15 – Jan 29 | Apr 9 – Apr 23 | — | — |
| Tomatoes | Jan 29 – Feb 12 | Apr 2 – Apr 16 | — | — |
| Lettuce | Jan 29 – Feb 12 | Mar 5 – Mar 19 | Feb 26 – Apr 2 | Sep 12 – Oct 10 |
| Kale | Jan 29 – Feb 12 | Feb 26 – Mar 12 | Feb 26 – Mar 12 | Aug 29 – Sep 19 |
| Broccoli | Jan 29 – Feb 12 | Mar 12 – Mar 26 | — | Aug 1 – Aug 22 |
| Cabbage | Jan 29 – Feb 12 | Mar 5 – Mar 19 | — | Aug 1 – Aug 22 |
| Cauliflower | Jan 29 – Feb 12 | Mar 12 – Mar 26 | — | Aug 1 – Aug 22 |
| Okra | Feb 12 – Feb 26 | Apr 16 – Apr 30 | Apr 16 – Apr 30 | — |
| Basil | Feb 12 – Feb 26 | Apr 2 – Apr 16 | — | — |
| Peas | — | — | Feb 12 – Mar 5 | Aug 15 – Sep 5 |
| Spinach | — | — | Feb 12 – Mar 5 | Sep 12 – Oct 3 |
| Radishes | — | — | Feb 19 – Apr 2 | Sep 26 – Oct 17 |
| Cucumbers | Feb 26 – Mar 5 | Apr 9 – Apr 16 | Apr 2 – Apr 16 | Aug 22 – Sep 5 |
| Zucchini & Summer Squash | Feb 26 – Mar 5 | — | Apr 2 – Apr 16 | Aug 29 – Sep 12 |
| Winter Squash & Pumpkins | Feb 26 – Mar 5 | — | Apr 2 – Apr 16 | — |
| Melons & Watermelon | Feb 26 – Mar 5 | Apr 9 – Apr 23 | — | — |
| Carrots | — | — | Mar 5 – Apr 2 | Aug 15 – Aug 29 |
| Beets | — | — | Mar 5 – Apr 2 | Aug 29 – Sep 12 |
| Potatoes | — | — | Mar 5 – Mar 26 | — |
| Swiss Chard | — | — | Mar 12 – Apr 9 | Aug 29 – Sep 12 |
| Cilantro | — | — | Mar 12 – Apr 2 | Sep 12 – Oct 3 |
| Green Beans | — | — | Apr 2 – Apr 23 | Aug 22 – Sep 5 |
| Sweet Corn | — | — | Apr 2 – Apr 16 | — |
| Sweet Potatoes | — | Apr 9 – Apr 30 | — | — |
| Garlic | — | — | — | Oct 24 – Nov 28 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Lawton, OK weather station, 8 km away (elevation 1,152 ft (351 m)).
Frost dates near Fort Sill
- Lawton Mar 26 · Nov 7
- Medicine Park Mar 21 · Nov 12
- Elgin Mar 21 · Nov 12
- Geronimo Apr 1 · Nov 5
- Cache Mar 21 · Nov 12
- Meers Mar 21 · Nov 12
- Fletcher Apr 4 · Oct 31
- Sterling Apr 4 · Oct 31
- Faxon Apr 7 · Nov 2
- Apache Apr 3 · Nov 3
Frequently asked questions
When is the last frost in Fort Sill, OK?
The median last spring frost in Fort Sill, OK is March 26. There is still about a 10% chance of frost after April 14, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Fort Sill, OK?
The median first fall frost is November 7, with about a 10% chance of frost before October 21.
How long is the growing season in Fort Sill, OK?
About 226 days between the median last spring frost and first fall frost.
What planting zone is Fort Sill, OK?
Fort Sill, OK is in USDA hardiness zone 8a.