Frost dates for 99185Wilbur, WA
The average last spring frost in Wilbur is June 1 and the average first fall frost is September 22, giving a typical growing season of about 112 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Jun 1
- Average first fall frost
- Sep 22
- Growing season
- 112 days
Safer after Jun 22 (1-in-10 risk)
Possible by Sep 2 (1-in-10 risk)
Last frost typically in 211 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) | — | — | 72 days | 100% |
| Frost / freeze (32°F) | May 10 · Jun 1 · Jun 22 | Sep 2 · Sep 22 · Oct 5 | 112 days | 100% |
| Hard freeze (28°F) | Apr 24 · May 8 · Jun 1 | Sep 18 · Oct 3 · Oct 20 | 148 days | 100% |
Planting calendar for Wilbur
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 | May 1 – Jul 7 |
| Tomatoes | Transplant outdoors | Jun 17 – Jun 2 |
| Peppers | Start seeds indoors | May 1 – Jun 1 |
| Peppers | Transplant outdoors | Jul 1 – Aug 1 |
| Eggplant | Start seeds indoors | May 18 – Jun 16 |
| Eggplant | Transplant outdoors | Jul 1 – Aug 1 |
| Cucumbers | Sow outdoors | Jul 1 – Jun 12 |
| Summer squash | Sow outdoors | Jun 17 – Aug 1 |
| Winter squash & pumpkins | Sow outdoors | Jul 1 – Aug 1 |
| Snap beans | Sow outdoors | Jun 17 – Jul 5 |
| Sweet corn | Sow outdoors | Jun 17 – Jun 2 |
| Watermelon & cantaloupe | Sow outdoors | Jul 1 – Aug 1 |
| Okra | Sow outdoors | Jun 24 – Jul 17 |
| Peas | Sow outdoors (spring) | May 1 – Jun 16 |
| Potatoes | Plant outdoors (spring) | May 1 – Jul 1 |
| Onions | Start seeds indoors (spring) | Mar 20 – Apr 16 |
| Onions | Transplant outdoors (spring) | May 18 – Jun 16 |
| Broccoli | Start seeds indoors (spring) | Apr 13 – May 17 |
| Broccoli | Transplant outdoors (spring) | May 18 – Jun 16 |
| Broccoli | Start seeds indoors (fall) | May 23 – Jun 2 |
| Broccoli | Transplant outdoors (fall) | Jun 22 – Jul 3 |
| Cabbage | Start seeds indoors (spring) | Apr 3 – May 1 |
| Cabbage | Transplant outdoors (spring) | May 1 – Jun 1 |
| Cabbage | Start seeds indoors (fall) | May 13 – Jun 12 |
| Cabbage | Transplant outdoors (fall) | Jun 12 – Jul 13 |
| Leaf lettuce | Sow outdoors (spring) | May 1 – Jul 17 |
| Leaf lettuce | Sow outdoors (fall) | Jun 12 – Jul 29 |
| Spinach | Sow outdoors (spring) | Apr 24 – Jun 7 |
| Spinach | Sow outdoors (fall) | Jun 29 – Aug 3 |
| Radishes | Sow outdoors (spring) | May 1 – Jun 21 |
| Radishes | Sow outdoors (fall) | Jun 12 – Aug 13 |
| Kale | Sow outdoors (spring) | May 18 – Jun 7 |
| Kale | Sow outdoors (fall) | Jun 5 – Jul 13 |
| Carrots | Sow outdoors (spring) | Jun 1 – Jul 17 |
| Carrots | Sow outdoors (fall) | May 13 – Jun 28 |
| Garlic | Plant outdoors (fall) | Sep 12 – Oct 13 |
Where these dates come from
ZIP code 99185 is matched to the NOAA station Wilbur, WA, 3.3 km away, at 2,262 ft elevation (51 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Wilbur, WA (used) | 2,262 ft | Jun 1 | Sep 22 |
| Hartline, WA | 1,906 ft | May 2 | Oct 12 |
| Coulee Dam 1 Sw, WA | 1,719 ft | Apr 22 | Oct 21 |
| Davenport, WA | 2,369 ft | Jun 6 | Sep 11 |
Frost dates near Wilbur
- Creston, WA 99117 · last Jun 1, first Sep 22
- Almira, WA 99103 · last Jun 1, first Sep 22
- Lincoln, WA 99147 · last Apr 22, first Oct 21
- Grand Coulee, WA 99133 · last Apr 22, first Oct 21
- Electric City, WA 99123 · last Apr 22, first Oct 21
- Keller, WA 99140 · last Apr 22, first Oct 21
- Hartline, WA 99135 · last May 2, first Oct 12
- Elmer City, WA 99124 · last Apr 22, first Oct 21
Frequently asked questions
- When is the last frost in Wilbur, WA?
- For ZIP code 99185, the average last spring frost (32°F) is June 1, based on NOAA 1991-2020 climate normals for the Wilbur, WA weather station. There is a 1-in-10 chance of a frost after June 22.
- When is the first frost in Wilbur, WA?
- The average first fall frost (32°F) is September 22. There is a 1-in-10 chance of frost by September 2, so tender plants are at risk from that point on.
- How long is the growing season in 99185?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 112 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.