Frost dates for 83636Letha, ID
The average last spring frost in Letha is April 30 and the average first fall frost is October 17, giving a typical growing season of about 168 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 30
- Average first fall frost
- Oct 17
- Growing season
- 168 days
Safer after May 17 (1-in-10 risk)
Possible by Oct 2 (1-in-10 risk)
Last frost typically in 179 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 1 · May 16 · Jun 5 | Sep 20 · Oct 4 · Oct 18 | 140 days | 100% |
| Frost / freeze (32°F) | Apr 17 · Apr 30 · May 17 | Oct 2 · Oct 17 · Nov 1 | 168 days | 100% |
| Hard freeze (28°F) | Mar 26 · Apr 14 · May 3 | Oct 15 · Oct 28 · Nov 13 | 197 days | 100% |
Planting calendar for Letha
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 30 – Jun 5 |
| Tomatoes | Transplant outdoors | May 16 – Jun 27 |
| Peppers | Start seeds indoors | Mar 30 – Apr 30 |
| Peppers | Transplant outdoors | May 30 – Jun 30 |
| Eggplant | Start seeds indoors | Apr 16 – May 15 |
| Eggplant | Transplant outdoors | May 30 – Jun 30 |
| Cucumbers | Sow outdoors | May 30 – Jul 7 |
| Summer squash | Sow outdoors | May 16 – Jun 30 |
| Winter squash & pumpkins | Sow outdoors | May 30 – Jun 30 |
| Snap beans | Sow outdoors | May 16 – Jul 30 |
| Sweet corn | Sow outdoors | May 16 – Jun 27 |
| Watermelon & cantaloupe | Sow outdoors | May 30 – Jun 30 |
| Okra | Sow outdoors | May 23 – Jun 15 |
| Peas | Sow outdoors (spring) | Mar 30 – May 15 |
| Potatoes | Plant outdoors (spring) | Mar 30 – May 30 |
| Onions | Start seeds indoors (spring) | Feb 16 – Mar 15 |
| Onions | Transplant outdoors (spring) | Apr 16 – May 15 |
| Broccoli | Start seeds indoors (spring) | Mar 12 – Apr 15 |
| Broccoli | Transplant outdoors (spring) | Apr 16 – May 15 |
| Broccoli | Start seeds indoors (fall) | Jun 17 – Jun 27 |
| Broccoli | Transplant outdoors (fall) | Jul 17 – Jul 28 |
| Cabbage | Start seeds indoors (spring) | Mar 2 – Mar 30 |
| Cabbage | Transplant outdoors (spring) | Mar 30 – Apr 30 |
| Cabbage | Start seeds indoors (fall) | Jun 7 – Jul 7 |
| Cabbage | Transplant outdoors (fall) | Jul 7 – Aug 7 |
| Leaf lettuce | Sow outdoors (spring) | Mar 30 – Jun 15 |
| Leaf lettuce | Sow outdoors (fall) | Jul 7 – Aug 23 |
| Spinach | Sow outdoors (spring) | Mar 23 – May 6 |
| Spinach | Sow outdoors (fall) | Jul 24 – Aug 28 |
| Radishes | Sow outdoors (spring) | Mar 30 – May 20 |
| Radishes | Sow outdoors (fall) | Jul 7 – Sep 7 |
| Kale | Sow outdoors (spring) | Apr 16 – May 6 |
| Kale | Sow outdoors (fall) | Jun 30 – Aug 7 |
| Carrots | Sow outdoors (spring) | Apr 30 – Jun 15 |
| Carrots | Sow outdoors (fall) | Jun 7 – Jul 23 |
| Garlic | Plant outdoors (fall) | Oct 7 – Nov 7 |
Where these dates come from
ZIP code 83636 is matched to the NOAA station Emmett 2 E, ID, 15.1 km away, at 2,390 ft elevation (103 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Emmett 2 E, ID (used) | 2,390 ft | Apr 30 | Oct 17 |
| Parma Exp Stn, ID | 2,290 ft | Apr 27 | Oct 9 |
| Nyssa, OR | 2,175 ft | Apr 18 | Oct 18 |
| Payette, ID | 2,150 ft | Apr 19 | Oct 20 |
Frost dates near Letha
- Emmett, ID 83617 · last Apr 30, first Oct 17
- New Plymouth, ID 83655 · last Apr 23, first Oct 13
- Middleton, ID 83644 · last Apr 29, first Oct 13
- Nampa, ID 83652 · last Apr 29, first Oct 13
- Notus, ID 83656 · last Apr 27, first Oct 9
- Caldwell, ID 83606 · last Apr 27, first Oct 9
- Mountain Home Afb, ID 83648 · last Apr 30, first Oct 17
- Fruitland, ID 83619 · last Apr 21, first Oct 14
Frequently asked questions
- When is the last frost in Letha, ID?
- For ZIP code 83636, the average last spring frost (32°F) is April 30, based on NOAA 1991-2020 climate normals for the Emmett 2 E, ID weather station. There is a 1-in-10 chance of a frost after May 17.
- When is the first frost in Letha, ID?
- The average first fall frost (32°F) is October 17. There is a 1-in-10 chance of frost by October 2, so tender plants are at risk from that point on.
- How long is the growing season in 83636?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 168 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.