Frost dates for 98856Twisp, WA
The average last spring frost in Twisp is May 15 and the average first fall frost is September 22, giving a typical growing season of about 127 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 15
- Average first fall frost
- Sep 22
- Growing season
- 127 days
Safer after Jun 1 (1-in-10 risk)
Possible by Sep 10 (1-in-10 risk)
Last frost typically in 193 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) | May 16 · Jun 1 · Jun 18 | Aug 30 · Sep 9 · Sep 21 | 100 days | 100% |
| Frost / freeze (32°F) | Apr 30 · May 15 · Jun 1 | Sep 10 · Sep 22 · Oct 2 | 127 days | 100% |
| Hard freeze (28°F) | Apr 17 · May 1 · May 15 | Sep 22 · Oct 3 · Oct 17 | 156 days | 100% |
Planting calendar for Twisp
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 | Apr 14 – Jun 20 |
| Tomatoes | Transplant outdoors | May 31 – Jun 2 |
| Peppers | Start seeds indoors | Apr 14 – May 15 |
| Peppers | Transplant outdoors | Jun 14 – Jul 15 |
| Eggplant | Start seeds indoors | May 1 – May 30 |
| Eggplant | Transplant outdoors | Jun 14 – Jul 15 |
| Cucumbers | Sow outdoors | Jun 14 – Jun 12 |
| Summer squash | Sow outdoors | May 31 – Jul 15 |
| Winter squash & pumpkins | Sow outdoors | Jun 14 – Jul 15 |
| Snap beans | Sow outdoors | May 31 – Jul 5 |
| Sweet corn | Sow outdoors | May 31 – Jun 2 |
| Watermelon & cantaloupe | Sow outdoors | Jun 14 – Jul 15 |
| Okra | Sow outdoors | Jun 7 – Jun 30 |
| Peas | Sow outdoors (spring) | Apr 14 – May 30 |
| Potatoes | Plant outdoors (spring) | Apr 14 – Jun 14 |
| Onions | Start seeds indoors (spring) | Mar 3 – Mar 30 |
| Onions | Transplant outdoors (spring) | May 1 – May 30 |
| Broccoli | Start seeds indoors (spring) | Mar 27 – Apr 30 |
| Broccoli | Transplant outdoors (spring) | May 1 – May 30 |
| Broccoli | Start seeds indoors (fall) | May 23 – Jun 2 |
| Broccoli | Transplant outdoors (fall) | Jun 22 – Jul 3 |
| Cabbage | Start seeds indoors (spring) | Mar 17 – Apr 14 |
| Cabbage | Transplant outdoors (spring) | Apr 14 – May 15 |
| Cabbage | Start seeds indoors (fall) | May 13 – Jun 12 |
| Cabbage | Transplant outdoors (fall) | Jun 12 – Jul 13 |
| Leaf lettuce | Sow outdoors (spring) | Apr 14 – Jun 30 |
| Leaf lettuce | Sow outdoors (fall) | Jun 12 – Jul 29 |
| Spinach | Sow outdoors (spring) | Apr 7 – May 21 |
| Spinach | Sow outdoors (fall) | Jun 29 – Aug 3 |
| Radishes | Sow outdoors (spring) | Apr 14 – Jun 4 |
| Radishes | Sow outdoors (fall) | Jun 12 – Aug 13 |
| Kale | Sow outdoors (spring) | May 1 – May 21 |
| Kale | Sow outdoors (fall) | Jun 5 – Jul 13 |
| Carrots | Sow outdoors (spring) | May 15 – Jun 30 |
| Carrots | Sow outdoors (fall) | May 13 – Jun 28 |
| Garlic | Plant outdoors (fall) | Sep 12 – Oct 13 |
Where these dates come from
ZIP code 98856 is matched to the NOAA station Winthrop 1 Wsw, WA, 13 km away, at 1,749 ft elevation (115 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Winthrop 1 Wsw, WA (used) | 1,749 ft | May 15 | Sep 22 |
| Methow 2 S, WA | 1,135 ft | Apr 21 | Oct 15 |
| Mazama, WA | 2,141 ft | May 9 | Sep 29 |
| Stehekin 4 Nw, WA | 1,257 ft | Apr 27 | Oct 17 |
Frost dates near Twisp
- Carlton, WA 98814 · last Apr 21, first Oct 15
- Winthrop, WA 98862 · last May 15, first Sep 22
- Methow, WA 98834 · last May 25, first Sep 19
- Malott, WA 98829 · last Apr 30, first Oct 7
- Mazama, WA 98833 · last May 9, first Sep 29
- Conconully, WA 98819 · last May 9, first Sep 29
- Brewster, WA 98812 · last Apr 21, first Oct 15
- Pateros, WA 98846 · last May 14, first Oct 1
Frequently asked questions
- When is the last frost in Twisp, WA?
- For ZIP code 98856, the average last spring frost (32°F) is May 15, based on NOAA 1991-2020 climate normals for the Winthrop 1 Wsw, WA weather station. There is a 1-in-10 chance of a frost after June 1.
- When is the first frost in Twisp, WA?
- The average first fall frost (32°F) is September 22. There is a 1-in-10 chance of frost by September 10, so tender plants are at risk from that point on.
- How long is the growing season in 98856?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 127 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.