Frost dates for 73720Bison, OK
The average last spring frost in Bison is April 14 and the average first fall frost is October 30, giving a typical growing season of about 198 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 14
- Average first fall frost
- Oct 30
- Growing season
- 198 days
Safer after Apr 27 (1-in-10 risk)
Possible by Oct 17 (1-in-10 risk)
First frost typically in 5 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Apr 10 · Apr 23 · May 5 | Oct 6 · Oct 21 · Nov 2 | 180 days | 100% |
| Frost / freeze (32°F) | Mar 29 · Apr 14 · Apr 27 | Oct 17 · Oct 30 · Nov 11 | 198 days | 100% |
| Hard freeze (28°F) | Mar 13 · Apr 2 · Apr 18 | Oct 25 · Nov 6 · Nov 22 | 218 days | 100% |
Planting calendar for Bison
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Mar 14 – May 20 |
| Tomatoes | Transplant outdoors | Apr 30 – Jul 10 |
| Peppers | Start seeds indoors | Mar 14 – Apr 14 |
| Peppers | Transplant outdoors | May 14 – Jun 14 |
| Eggplant | Start seeds indoors | Mar 31 – Apr 29 |
| Eggplant | Transplant outdoors | May 14 – Jun 14 |
| Cucumbers | Sow outdoors | May 14 – Jul 20 |
| Summer squash | Sow outdoors | Apr 30 – Jun 14 |
| Winter squash & pumpkins | Sow outdoors | May 14 – Jun 14 |
| Snap beans | Sow outdoors | Apr 30 – Aug 12 |
| Sweet corn | Sow outdoors | Apr 30 – Jul 10 |
| Watermelon & cantaloupe | Sow outdoors | May 14 – Jun 14 |
| Okra | Sow outdoors | May 7 – May 30 |
| Peas | Sow outdoors (spring) | Mar 14 – Apr 29 |
| Potatoes | Plant outdoors (spring) | Mar 14 – May 14 |
| Onions | Start seeds indoors (spring) | Jan 31 – Feb 27 |
| Onions | Transplant outdoors (spring) | Mar 31 – Apr 29 |
| Broccoli | Start seeds indoors (spring) | Feb 24 – Mar 30 |
| Broccoli | Transplant outdoors (spring) | Mar 31 – Apr 29 |
| Broccoli | Start seeds indoors (fall) | Jun 30 – Jul 10 |
| Broccoli | Transplant outdoors (fall) | Jul 30 – Aug 10 |
| Cabbage | Start seeds indoors (spring) | Feb 14 – Mar 14 |
| Cabbage | Transplant outdoors (spring) | Mar 14 – Apr 14 |
| Cabbage | Start seeds indoors (fall) | Jun 20 – Jul 20 |
| Cabbage | Transplant outdoors (fall) | Jul 20 – Aug 20 |
| Leaf lettuce | Sow outdoors (spring) | Mar 14 – May 30 |
| Leaf lettuce | Sow outdoors (fall) | Jul 20 – Sep 5 |
| Spinach | Sow outdoors (spring) | Mar 7 – Apr 20 |
| Spinach | Sow outdoors (fall) | Aug 6 – Sep 10 |
| Radishes | Sow outdoors (spring) | Mar 14 – May 4 |
| Radishes | Sow outdoors (fall) | Jul 20 – Sep 20 |
| Kale | Sow outdoors (spring) | Mar 31 – Apr 20 |
| Kale | Sow outdoors (fall) | Jul 13 – Aug 20 |
| Carrots | Sow outdoors (spring) | Apr 14 – May 30 |
| Carrots | Sow outdoors (fall) | Jun 20 – Aug 5 |
| Garlic | Plant outdoors (fall) | Oct 20 – Nov 20 |
Where these dates come from
ZIP code 73720 is matched to the NOAA station Hennessey 4 Ese, OK, 12.1 km away, at 1,174 ft elevation (30 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Hennessey 4 Ese, OK (used) | 1,174 ft | Apr 14 | Oct 30 |
| Enid, OK | 1,245 ft | Apr 6 | Nov 1 |
| Marshall 3Sse Mesonet, OK | 1,020 ft | Apr 11 | Oct 31 |
| Breckinridge 3Se Mesnt, OK | 1,154 ft | Apr 10 | Oct 29 |
Frost dates near Bison
- Waukomis, OK 73773 · last Apr 6, first Nov 1
- Hennessey, OK 73742 · last Apr 14, first Oct 30
- Enid, OK 73705 · last Apr 6, first Nov 1
- Drummond, OK 73735 · last Apr 6, first Nov 1
- Douglas, OK 73733 · last Apr 14, first Oct 30
- Dover, OK 73734 · last Apr 8, first Nov 1
- Fairmont, OK 73736 · last Apr 6, first Nov 1
- Marshall, OK 73056 · last Apr 11, first Oct 31
Frequently asked questions
- When is the last frost in Bison, OK?
- For ZIP code 73720, the average last spring frost (32°F) is April 14, based on NOAA 1991-2020 climate normals for the Hennessey 4 Ese, OK weather station. There is a 1-in-10 chance of a frost after April 27.
- When is the first frost in Bison, OK?
- The average first fall frost (32°F) is October 30. There is a 1-in-10 chance of frost by October 17, so tender plants are at risk from that point on.
- How long is the growing season in 73720?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 198 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.