Frost dates for 73086Sulphur, OK
The average last spring frost in Sulphur is April 4 and the average first fall frost is October 31, giving a typical growing season of about 208 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 4
- Average first fall frost
- Oct 31
- Growing season
- 208 days
Safer after Apr 22 (1-in-10 risk)
Possible by Oct 17 (1-in-10 risk)
First frost typically in 6 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 1 · Apr 17 · May 1 | Oct 6 · Oct 22 · Nov 5 | 188 days | 100% |
| Frost / freeze (32°F) | Mar 16 · Apr 4 · Apr 22 | Oct 17 · Oct 31 · Nov 15 | 208 days | 100% |
| Hard freeze (28°F) | Mar 2 · Mar 23 · Apr 12 | Oct 24 · Nov 9 · Nov 28 | 233 days | 100% |
Planting calendar for Sulphur
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 4 – May 10 |
| Tomatoes | Transplant outdoors | Apr 20 – Jul 11 |
| Peppers | Start seeds indoors | Mar 4 – Apr 4 |
| Peppers | Transplant outdoors | May 4 – Jun 4 |
| Eggplant | Start seeds indoors | Mar 21 – Apr 19 |
| Eggplant | Transplant outdoors | May 4 – Jun 4 |
| Cucumbers | Sow outdoors | May 4 – Jul 21 |
| Summer squash | Sow outdoors | Apr 20 – Jun 4 |
| Winter squash & pumpkins | Sow outdoors | May 4 – Jun 4 |
| Snap beans | Sow outdoors | Apr 20 – Aug 13 |
| Sweet corn | Sow outdoors | Apr 20 – Jul 11 |
| Watermelon & cantaloupe | Sow outdoors | May 4 – Jun 4 |
| Okra | Sow outdoors | Apr 27 – May 20 |
| Peas | Sow outdoors (spring) | Mar 4 – Apr 19 |
| Potatoes | Plant outdoors (spring) | Mar 4 – May 4 |
| Onions | Start seeds indoors (spring) | Jan 21 – Feb 17 |
| Onions | Transplant outdoors (spring) | Mar 21 – Apr 19 |
| Broccoli | Start seeds indoors (spring) | Feb 14 – Mar 20 |
| Broccoli | Transplant outdoors (spring) | Mar 21 – Apr 19 |
| Broccoli | Start seeds indoors (fall) | Jul 1 – Jul 11 |
| Broccoli | Transplant outdoors (fall) | Jul 31 – Aug 11 |
| Cabbage | Start seeds indoors (spring) | Feb 4 – Mar 4 |
| Cabbage | Transplant outdoors (spring) | Mar 4 – Apr 4 |
| Cabbage | Start seeds indoors (fall) | Jun 21 – Jul 21 |
| Cabbage | Transplant outdoors (fall) | Jul 21 – Aug 21 |
| Leaf lettuce | Sow outdoors (spring) | Mar 4 – May 20 |
| Leaf lettuce | Sow outdoors (fall) | Jul 21 – Sep 6 |
| Spinach | Sow outdoors (spring) | Feb 25 – Apr 10 |
| Spinach | Sow outdoors (fall) | Aug 7 – Sep 11 |
| Radishes | Sow outdoors (spring) | Mar 4 – Apr 24 |
| Radishes | Sow outdoors (fall) | Jul 21 – Sep 21 |
| Kale | Sow outdoors (spring) | Mar 21 – Apr 10 |
| Kale | Sow outdoors (fall) | Jul 14 – Aug 21 |
| Carrots | Sow outdoors (spring) | Apr 4 – May 20 |
| Carrots | Sow outdoors (fall) | Jun 21 – Aug 6 |
| Garlic | Plant outdoors (fall) | Oct 21 – Nov 21 |
Where these dates come from
ZIP code 73086 is matched to the NOAA station Chickasaw Nra, OK, 1.9 km away, at 1,047 ft elevation (82 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Chickasaw Nra, OK (used) | 1,047 ft | Apr 4 | Oct 31 |
| Sulphur 4Nne Mesonet, OK | 1,049 ft | Apr 4 | Nov 1 |
| Fittstown 6Sw Mesonet, OK | 1,148 ft | Mar 29 | Nov 6 |
| Pauls Vly 1Ssw Mesonet, OK | 954 ft | Mar 28 | Nov 7 |
Frost dates near Sulphur
- Davis, OK 73030 · last Apr 4, first Oct 31
- Dougherty, OK 73032 · last Apr 4, first Oct 31
- Roff, OK 74865 · last Apr 4, first Oct 31
- Wynnewood, OK 73098 · last Apr 5, first Nov 1
- Gene Autry, OK 73436 · last Mar 18, first Nov 10
- Fitzhugh, OK 74843 · last Apr 2, first Nov 4
- Springer, OK 73458 · last Mar 18, first Nov 10
- Mill Creek, OK 74856 · last Mar 29, first Nov 5
Frequently asked questions
- When is the last frost in Sulphur, OK?
- For ZIP code 73086, the average last spring frost (32°F) is April 4, based on NOAA 1991-2020 climate normals for the Chickasaw Nra, OK weather station. There is a 1-in-10 chance of a frost after April 22.
- When is the first frost in Sulphur, OK?
- The average first fall frost (32°F) is October 31. 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 73086?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 208 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.