Frost dates for 83555Winchester, ID
The average last spring frost in Winchester is May 23 and the average first fall frost is September 25, giving a typical growing season of about 121 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 23
- Average first fall frost
- Sep 25
- Growing season
- 121 days
Safer after Jun 19 (1-in-10 risk)
Possible by Sep 7 (1-in-10 risk)
Last frost typically in 201 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) | Jun 1 · Jun 18 · Jul 12 | Aug 21 · Sep 8 · Sep 26 | 80 days | 100% |
| Frost / freeze (32°F) | May 4 · May 23 · Jun 19 | Sep 7 · Sep 25 · Oct 10 | 121 days | 100% |
| Hard freeze (28°F) | Apr 13 · May 2 · May 24 | Sep 21 · Oct 9 · Oct 28 | 160 days | 100% |
Planting calendar for Winchester
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 22 – Jun 28 |
| Tomatoes | Transplant outdoors | Jun 8 – Jun 5 |
| Peppers | Start seeds indoors | Apr 22 – May 23 |
| Peppers | Transplant outdoors | Jun 22 – Jul 23 |
| Eggplant | Start seeds indoors | May 9 – Jun 7 |
| Eggplant | Transplant outdoors | Jun 22 – Jul 23 |
| Cucumbers | Sow outdoors | Jun 22 – Jun 15 |
| Summer squash | Sow outdoors | Jun 8 – Jul 23 |
| Winter squash & pumpkins | Sow outdoors | Jun 22 – Jul 23 |
| Snap beans | Sow outdoors | Jun 8 – Jul 8 |
| Sweet corn | Sow outdoors | Jun 8 – Jun 5 |
| Watermelon & cantaloupe | Sow outdoors | Jun 22 – Jul 23 |
| Okra | Sow outdoors | Jun 15 – Jul 8 |
| Peas | Sow outdoors (spring) | Apr 22 – Jun 7 |
| Potatoes | Plant outdoors (spring) | Apr 22 – Jun 22 |
| Onions | Start seeds indoors (spring) | Mar 11 – Apr 7 |
| Onions | Transplant outdoors (spring) | May 9 – Jun 7 |
| Broccoli | Start seeds indoors (spring) | Apr 4 – May 8 |
| Broccoli | Transplant outdoors (spring) | May 9 – Jun 7 |
| Broccoli | Start seeds indoors (fall) | May 26 – Jun 5 |
| Broccoli | Transplant outdoors (fall) | Jun 25 – Jul 6 |
| Cabbage | Start seeds indoors (spring) | Mar 25 – Apr 22 |
| Cabbage | Transplant outdoors (spring) | Apr 22 – May 23 |
| Cabbage | Start seeds indoors (fall) | May 16 – Jun 15 |
| Cabbage | Transplant outdoors (fall) | Jun 15 – Jul 16 |
| Leaf lettuce | Sow outdoors (spring) | Apr 22 – Jul 8 |
| Leaf lettuce | Sow outdoors (fall) | Jun 15 – Aug 1 |
| Spinach | Sow outdoors (spring) | Apr 15 – May 29 |
| Spinach | Sow outdoors (fall) | Jul 2 – Aug 6 |
| Radishes | Sow outdoors (spring) | Apr 22 – Jun 12 |
| Radishes | Sow outdoors (fall) | Jun 15 – Aug 16 |
| Kale | Sow outdoors (spring) | May 9 – May 29 |
| Kale | Sow outdoors (fall) | Jun 8 – Jul 16 |
| Carrots | Sow outdoors (spring) | May 23 – Jul 8 |
| Carrots | Sow outdoors (fall) | May 16 – Jul 1 |
| Garlic | Plant outdoors (fall) | Sep 15 – Oct 16 |
Where these dates come from
ZIP code 83555 is matched to the NOAA station Winchester, ID, 0.2 km away, at 3,972 ft elevation (12 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Winchester, ID (used) | 3,972 ft | May 23 | Sep 25 |
| Cottonwood 2 Wsw, ID | 3,945 ft | May 6 | Oct 13 |
| Nezperce, ID | 3,248 ft | May 24 | Sep 20 |
| Lewiston Nez Perce Co Ap, ID | 1,436 ft | Apr 6 | Oct 26 |
Frost dates near Winchester
- Craigmont, ID 83523 · last May 23, first Sep 25
- Reubens, ID 83548 · last May 24, first Sep 20
- Culdesac, ID 83524 · last Apr 6, first Oct 26
- Ferdinand, ID 83526 · last May 6, first Oct 13
- Lewiston, ID 83501 · last Apr 6, first Oct 26
- Lapwai, ID 83540 · last Apr 6, first Oct 26
- Cottonwood, ID 83522 · last May 6, first Oct 13
- Nezperce, ID 83543 · last May 24, first Sep 20
Frequently asked questions
- When is the last frost in Winchester, ID?
- For ZIP code 83555, the average last spring frost (32°F) is May 23, based on NOAA 1991-2020 climate normals for the Winchester, ID weather station. There is a 1-in-10 chance of a frost after June 19.
- When is the first frost in Winchester, ID?
- The average first fall frost (32°F) is September 25. There is a 1-in-10 chance of frost by September 7, so tender plants are at risk from that point on.
- How long is the growing season in 83555?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 121 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.