Frost dates for 74959Spiro, OK
The average last spring frost in Spiro is March 25 and the average first fall frost is November 6, giving a typical growing season of about 224 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 25
- Average first fall frost
- Nov 6
- Growing season
- 224 days
Safer after Apr 11 (1-in-10 risk)
Possible by Oct 23 (1-in-10 risk)
First frost typically in 11 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) | Mar 21 · Apr 8 · Apr 25 | Oct 16 · Oct 28 · Nov 11 | 203 days | 100% |
| Frost / freeze (32°F) | Mar 4 · Mar 25 · Apr 11 | Oct 23 · Nov 6 · Nov 21 | 224 days | 100% |
| Hard freeze (28°F) | Feb 21 · Mar 11 · Apr 2 | Nov 1 · Nov 17 · Dec 4 | 250 days | 100% |
Planting calendar for Spiro
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 | Feb 22 – Apr 30 |
| Tomatoes | Transplant outdoors | Apr 10 – Jul 17 |
| Peppers | Start seeds indoors | Feb 22 – Mar 25 |
| Peppers | Transplant outdoors | Apr 24 – May 25 |
| Eggplant | Start seeds indoors | Mar 11 – Apr 9 |
| Eggplant | Transplant outdoors | Apr 24 – May 25 |
| Cucumbers | Sow outdoors | Apr 24 – Jul 27 |
| Summer squash | Sow outdoors | Apr 10 – May 25 |
| Winter squash & pumpkins | Sow outdoors | Apr 24 – May 25 |
| Snap beans | Sow outdoors | Apr 10 – Aug 19 |
| Sweet corn | Sow outdoors | Apr 10 – Jul 17 |
| Watermelon & cantaloupe | Sow outdoors | Apr 24 – May 25 |
| Okra | Sow outdoors | Apr 17 – May 10 |
| Peas | Sow outdoors (spring) | Feb 22 – Apr 9 |
| Potatoes | Plant outdoors (spring) | Feb 22 – Apr 24 |
| Onions | Start seeds indoors (spring) | Jan 11 – Feb 7 |
| Onions | Transplant outdoors (spring) | Mar 11 – Apr 9 |
| Broccoli | Start seeds indoors (spring) | Feb 4 – Mar 10 |
| Broccoli | Transplant outdoors (spring) | Mar 11 – Apr 9 |
| Broccoli | Start seeds indoors (fall) | Jul 7 – Jul 17 |
| Broccoli | Transplant outdoors (fall) | Aug 6 – Aug 17 |
| Cabbage | Start seeds indoors (spring) | Jan 25 – Feb 22 |
| Cabbage | Transplant outdoors (spring) | Feb 22 – Mar 25 |
| Cabbage | Start seeds indoors (fall) | Jun 27 – Jul 27 |
| Cabbage | Transplant outdoors (fall) | Jul 27 – Aug 27 |
| Leaf lettuce | Sow outdoors (spring) | Feb 22 – May 10 |
| Leaf lettuce | Sow outdoors (fall) | Jul 27 – Sep 12 |
| Spinach | Sow outdoors (spring) | Feb 15 – Mar 31 |
| Spinach | Sow outdoors (fall) | Aug 13 – Sep 17 |
| Radishes | Sow outdoors (spring) | Feb 22 – Apr 14 |
| Radishes | Sow outdoors (fall) | Jul 27 – Sep 27 |
| Kale | Sow outdoors (spring) | Mar 11 – Mar 31 |
| Kale | Sow outdoors (fall) | Jul 20 – Aug 27 |
| Carrots | Sow outdoors (spring) | Mar 25 – May 10 |
| Carrots | Sow outdoors (fall) | Jun 27 – Aug 12 |
| Garlic | Plant outdoors (fall) | Oct 27 – Nov 27 |
Where these dates come from
ZIP code 74959 is matched to the NOAA station Ft Smith Rgnl Ap, AR, 25.7 km away, at 449 ft elevation (66 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Ft Smith Rgnl Ap, AR (used) | 449 ft | Mar 25 | Nov 6 |
| Sallisaw 2 Nw, OK | 660 ft | Mar 30 | Nov 7 |
| Mc Curtain 1 Se, OK | 655 ft | Mar 23 | Nov 5 |
| Wister 3S, OK | 525 ft | Apr 6 | Nov 2 |
Frost dates near Spiro
- Panama, OK 74951 · last Mar 25, first Nov 6
- Pocola, OK 74902 · last Mar 25, first Nov 6
- Shady Point, OK 74956 · last Mar 23, first Nov 5
- Cameron, OK 74932 · last Mar 25, first Nov 6
- Bokoshe, OK 74930 · last Mar 23, first Nov 5
- Muldrow, OK 74948 · last Mar 30, first Nov 7
- Gans, OK 74936 · last Mar 30, first Nov 7
- Arkoma, OK 74901 · last Mar 25, first Nov 6
Frequently asked questions
- When is the last frost in Spiro, OK?
- For ZIP code 74959, the average last spring frost (32°F) is March 25, based on NOAA 1991-2020 climate normals for the Ft Smith Rgnl Ap, AR weather station. There is a 1-in-10 chance of a frost after April 11.
- When is the first frost in Spiro, OK?
- The average first fall frost (32°F) is November 6. There is a 1-in-10 chance of frost by October 23, so tender plants are at risk from that point on.
- How long is the growing season in 74959?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 224 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.