Frost dates for 98946Thorp, WA
The average last spring frost in Thorp is April 28 and the average first fall frost is October 7, giving a typical growing season of about 163 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 28
- Average first fall frost
- Oct 7
- Growing season
- 163 days
Safer after May 12 (1-in-10 risk)
Possible by Sep 26 (1-in-10 risk)
Last frost typically in 185 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 28 · May 11 · Jun 5 | Sep 12 · Sep 26 · Oct 7 | 135 days | 100% |
| Frost / freeze (32°F) | Apr 13 · Apr 28 · May 12 | Sep 26 · Oct 7 · Oct 22 | 163 days | 100% |
| Hard freeze (28°F) | Mar 24 · Apr 11 · Apr 30 | Oct 7 · Oct 20 · Nov 3 | 191 days | 100% |
Planting calendar for Thorp
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 28 – Jun 3 |
| Tomatoes | Transplant outdoors | May 14 – Jun 17 |
| Peppers | Start seeds indoors | Mar 28 – Apr 28 |
| Peppers | Transplant outdoors | May 28 – Jun 28 |
| Eggplant | Start seeds indoors | Apr 14 – May 13 |
| Eggplant | Transplant outdoors | May 28 – Jun 28 |
| Cucumbers | Sow outdoors | May 28 – Jun 27 |
| Summer squash | Sow outdoors | May 14 – Jun 28 |
| Winter squash & pumpkins | Sow outdoors | May 28 – Jun 28 |
| Snap beans | Sow outdoors | May 14 – Jul 20 |
| Sweet corn | Sow outdoors | May 14 – Jun 17 |
| Watermelon & cantaloupe | Sow outdoors | May 28 – Jun 28 |
| Okra | Sow outdoors | May 21 – Jun 13 |
| Peas | Sow outdoors (spring) | Mar 28 – May 13 |
| Potatoes | Plant outdoors (spring) | Mar 28 – May 28 |
| Onions | Start seeds indoors (spring) | Feb 14 – Mar 13 |
| Onions | Transplant outdoors (spring) | Apr 14 – May 13 |
| Broccoli | Start seeds indoors (spring) | Mar 10 – Apr 13 |
| Broccoli | Transplant outdoors (spring) | Apr 14 – May 13 |
| Broccoli | Start seeds indoors (fall) | Jun 7 – Jun 17 |
| Broccoli | Transplant outdoors (fall) | Jul 7 – Jul 18 |
| Cabbage | Start seeds indoors (spring) | Feb 28 – Mar 28 |
| Cabbage | Transplant outdoors (spring) | Mar 28 – Apr 28 |
| Cabbage | Start seeds indoors (fall) | May 28 – Jun 27 |
| Cabbage | Transplant outdoors (fall) | Jun 27 – Jul 28 |
| Leaf lettuce | Sow outdoors (spring) | Mar 28 – Jun 13 |
| Leaf lettuce | Sow outdoors (fall) | Jun 27 – Aug 13 |
| Spinach | Sow outdoors (spring) | Mar 21 – May 4 |
| Spinach | Sow outdoors (fall) | Jul 14 – Aug 18 |
| Radishes | Sow outdoors (spring) | Mar 28 – May 18 |
| Radishes | Sow outdoors (fall) | Jun 27 – Aug 28 |
| Kale | Sow outdoors (spring) | Apr 14 – May 4 |
| Kale | Sow outdoors (fall) | Jun 20 – Jul 28 |
| Carrots | Sow outdoors (spring) | Apr 28 – Jun 13 |
| Carrots | Sow outdoors (fall) | May 28 – Jul 13 |
| Garlic | Plant outdoors (fall) | Sep 27 – Oct 28 |
Where these dates come from
ZIP code 98946 is matched to the NOAA station Ellensburg Bowers Fld, WA, 11.3 km away, at 1,766 ft elevation (129 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Ellensburg Bowers Fld, WA (used) | 1,766 ft | Apr 28 | Oct 7 |
| Ellensburg, WA | 1,480 ft | May 8 | Oct 2 |
| Cle Elum, WA | 1,900 ft | May 13 | Sep 25 |
| Easton, WA | 2,170 ft | May 9 | Oct 6 |
Frost dates near Thorp
- Ellensburg, WA 98926 · last May 8, first Oct 2
- Kittitas, WA 98934 · last Apr 28, first Oct 7
- South Cle Elum, WA 98943 · last May 13, first Sep 25
- Cle Elum, WA 98922 · last May 13, first Sep 25
- Roslyn, WA 98941 · last May 9, first Oct 6
- Ronald, WA 98940 · last May 9, first Oct 6
- Naches, WA 98937 · last May 9, first Oct 6
- Tieton, WA 98947 · last Apr 28, first Oct 7
Frequently asked questions
- When is the last frost in Thorp, WA?
- For ZIP code 98946, the average last spring frost (32°F) is April 28, based on NOAA 1991-2020 climate normals for the Ellensburg Bowers Fld, WA weather station. There is a 1-in-10 chance of a frost after May 12.
- When is the first frost in Thorp, WA?
- The average first fall frost (32°F) is October 7. There is a 1-in-10 chance of frost by September 26, so tender plants are at risk from that point on.
- How long is the growing season in 98946?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 163 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.