Frost dates for 99155Nespelem, WA
The average last spring frost in Nespelem is April 22 and the average first fall frost is October 21, giving a typical growing season of about 180 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 22
- Average first fall frost
- Oct 21
- Growing season
- 180 days
Safer after May 7 (1-in-10 risk)
Possible by Oct 6 (1-in-10 risk)
Last frost typically in 178 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 21 · May 5 · May 21 | Sep 27 · Oct 8 · Oct 24 | 156 days | 100% |
| Frost / freeze (32°F) | Apr 5 · Apr 22 · May 7 | Oct 6 · Oct 21 · Nov 5 | 180 days | 100% |
| Hard freeze (28°F) | Mar 14 · Apr 1 · Apr 19 | Oct 18 · Nov 1 · Nov 17 | 214 days | 100% |
Planting calendar for Nespelem
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 22 – May 28 |
| Tomatoes | Transplant outdoors | May 8 – Jul 1 |
| Peppers | Start seeds indoors | Mar 22 – Apr 22 |
| Peppers | Transplant outdoors | May 22 – Jun 22 |
| Eggplant | Start seeds indoors | Apr 8 – May 7 |
| Eggplant | Transplant outdoors | May 22 – Jun 22 |
| Cucumbers | Sow outdoors | May 22 – Jul 11 |
| Summer squash | Sow outdoors | May 8 – Jun 22 |
| Winter squash & pumpkins | Sow outdoors | May 22 – Jun 22 |
| Snap beans | Sow outdoors | May 8 – Aug 3 |
| Sweet corn | Sow outdoors | May 8 – Jul 1 |
| Watermelon & cantaloupe | Sow outdoors | May 22 – Jun 22 |
| Okra | Sow outdoors | May 15 – Jun 7 |
| Peas | Sow outdoors (spring) | Mar 22 – May 7 |
| Potatoes | Plant outdoors (spring) | Mar 22 – May 22 |
| Onions | Start seeds indoors (spring) | Feb 8 – Mar 7 |
| Onions | Transplant outdoors (spring) | Apr 8 – May 7 |
| Broccoli | Start seeds indoors (spring) | Mar 4 – Apr 7 |
| Broccoli | Transplant outdoors (spring) | Apr 8 – May 7 |
| Broccoli | Start seeds indoors (fall) | Jun 21 – Jul 1 |
| Broccoli | Transplant outdoors (fall) | Jul 21 – Aug 1 |
| Cabbage | Start seeds indoors (spring) | Feb 22 – Mar 22 |
| Cabbage | Transplant outdoors (spring) | Mar 22 – Apr 22 |
| Cabbage | Start seeds indoors (fall) | Jun 11 – Jul 11 |
| Cabbage | Transplant outdoors (fall) | Jul 11 – Aug 11 |
| Leaf lettuce | Sow outdoors (spring) | Mar 22 – Jun 7 |
| Leaf lettuce | Sow outdoors (fall) | Jul 11 – Aug 27 |
| Spinach | Sow outdoors (spring) | Mar 15 – Apr 28 |
| Spinach | Sow outdoors (fall) | Jul 28 – Sep 1 |
| Radishes | Sow outdoors (spring) | Mar 22 – May 12 |
| Radishes | Sow outdoors (fall) | Jul 11 – Sep 11 |
| Kale | Sow outdoors (spring) | Apr 8 – Apr 28 |
| Kale | Sow outdoors (fall) | Jul 4 – Aug 11 |
| Carrots | Sow outdoors (spring) | Apr 22 – Jun 7 |
| Carrots | Sow outdoors (fall) | Jun 11 – Jul 27 |
| Garlic | Plant outdoors (fall) | Oct 11 – Nov 11 |
Where these dates come from
ZIP code 99155 is matched to the NOAA station Coulee Dam 1 Sw, WA, 21 km away, at 1,719 ft elevation (203 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Coulee Dam 1 Sw, WA (used) | 1,719 ft | Apr 22 | Oct 21 |
| Wilbur, WA | 2,262 ft | Jun 1 | Sep 22 |
| Chief Joseph Dam, WA | 834 ft | Apr 26 | Oct 11 |
| Hartline, WA | 1,906 ft | May 2 | Oct 12 |
Frost dates near Nespelem
- Coulee Dam, WA 99116 · last Apr 22, first Oct 21
- Elmer City, WA 99124 · 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
- Mansfield, WA 98830 · last May 2, first Oct 12
- Almira, WA 99103 · last Jun 1, first Sep 22
- Omak, WA 98841 · last Apr 30, first Oct 7
Frequently asked questions
- When is the last frost in Nespelem, WA?
- For ZIP code 99155, the average last spring frost (32°F) is April 22, based on NOAA 1991-2020 climate normals for the Coulee Dam 1 Sw, WA weather station. There is a 1-in-10 chance of a frost after May 7.
- When is the first frost in Nespelem, WA?
- The average first fall frost (32°F) is October 21. There is a 1-in-10 chance of frost by October 6, so tender plants are at risk from that point on.
- How long is the growing season in 99155?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 180 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.