Frost dates for 99017Lamont, WA
The average last spring frost in Lamont is April 29 and the average first fall frost is October 4, giving a typical growing season of about 161 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 29
- Average first fall frost
- Oct 4
- Growing season
- 161 days
Safer after May 15 (1-in-10 risk)
Possible by Sep 19 (1-in-10 risk)
Last frost typically in 177 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 30 · May 16 · Jun 7 | Sep 4 · Sep 23 · Oct 9 | 126 days | 100% |
| Frost / freeze (32°F) | Apr 9 · Apr 29 · May 15 | Sep 19 · Oct 4 · Oct 23 | 161 days | 100% |
| Hard freeze (28°F) | Mar 11 · Apr 5 · Apr 29 | Oct 2 · Oct 20 · Nov 11 | 198 days | 100% |
Planting calendar for Lamont
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 29 – Jun 4 |
| Tomatoes | Transplant outdoors | May 15 – Jun 14 |
| Peppers | Start seeds indoors | Mar 29 – Apr 29 |
| Peppers | Transplant outdoors | May 29 – Jun 29 |
| Eggplant | Start seeds indoors | Apr 15 – May 14 |
| Eggplant | Transplant outdoors | May 29 – Jun 29 |
| Cucumbers | Sow outdoors | May 29 – Jun 24 |
| Summer squash | Sow outdoors | May 15 – Jun 29 |
| Winter squash & pumpkins | Sow outdoors | May 29 – Jun 29 |
| Snap beans | Sow outdoors | May 15 – Jul 17 |
| Sweet corn | Sow outdoors | May 15 – Jun 14 |
| Watermelon & cantaloupe | Sow outdoors | May 29 – Jun 29 |
| Okra | Sow outdoors | May 22 – Jun 14 |
| Peas | Sow outdoors (spring) | Mar 29 – May 14 |
| Potatoes | Plant outdoors (spring) | Mar 29 – May 29 |
| Onions | Start seeds indoors (spring) | Feb 15 – Mar 14 |
| Onions | Transplant outdoors (spring) | Apr 15 – May 14 |
| Broccoli | Start seeds indoors (spring) | Mar 11 – Apr 14 |
| Broccoli | Transplant outdoors (spring) | Apr 15 – May 14 |
| Broccoli | Start seeds indoors (fall) | Jun 4 – Jun 14 |
| Broccoli | Transplant outdoors (fall) | Jul 4 – Jul 15 |
| Cabbage | Start seeds indoors (spring) | Mar 1 – Mar 29 |
| Cabbage | Transplant outdoors (spring) | Mar 29 – Apr 29 |
| Cabbage | Start seeds indoors (fall) | May 25 – Jun 24 |
| Cabbage | Transplant outdoors (fall) | Jun 24 – Jul 25 |
| Leaf lettuce | Sow outdoors (spring) | Mar 29 – Jun 14 |
| Leaf lettuce | Sow outdoors (fall) | Jun 24 – Aug 10 |
| Spinach | Sow outdoors (spring) | Mar 22 – May 5 |
| Spinach | Sow outdoors (fall) | Jul 11 – Aug 15 |
| Radishes | Sow outdoors (spring) | Mar 29 – May 19 |
| Radishes | Sow outdoors (fall) | Jun 24 – Aug 25 |
| Kale | Sow outdoors (spring) | Apr 15 – May 5 |
| Kale | Sow outdoors (fall) | Jun 17 – Jul 25 |
| Carrots | Sow outdoors (spring) | Apr 29 – Jun 14 |
| Carrots | Sow outdoors (fall) | May 25 – Jul 10 |
| Garlic | Plant outdoors (fall) | Sep 24 – Oct 25 |
Where these dates come from
ZIP code 99017 is matched to the NOAA station St John, WA, 24.2 km away, at 1,952 ft elevation (118 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| St John, WA (used) | 1,952 ft | Apr 29 | Oct 4 |
| Spokane 17 Ssw, WA | 2,267 ft | May 30 | Sep 4 |
| Ritzville 1 Sse, WA | 1,864 ft | May 7 | Oct 10 |
| Rosalia, WA | 2,420 ft | May 7 | Sep 28 |
Frost dates near Lamont
- Sprague, WA 99032 · last May 31, first Sep 12
- Saint John, WA 99171 · last Apr 29, first Oct 4
- Endicott, WA 99125 · last May 13, first Sep 26
- Malden, WA 99149 · last May 7, first Sep 28
- Rosalia, WA 99170 · last May 7, first Sep 28
- Thornton, WA 99176 · last May 7, first Sep 28
- Edwall, WA 99008 · last Jun 6, first Sep 11
- Ritzville, WA 99169 · last May 7, first Oct 10
Frequently asked questions
- When is the last frost in Lamont, WA?
- For ZIP code 99017, the average last spring frost (32°F) is April 29, based on NOAA 1991-2020 climate normals for the St John, WA weather station. There is a 1-in-10 chance of a frost after May 15.
- When is the first frost in Lamont, WA?
- The average first fall frost (32°F) is October 4. There is a 1-in-10 chance of frost by September 19, so tender plants are at risk from that point on.
- How long is the growing season in 99017?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 161 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.