Frost dates for 99113Colton, WA
The average last spring frost in Colton is April 29 and the average first fall frost is October 2, giving a typical growing season of about 159 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 29
- Average first fall frost
- Oct 2
- Growing season
- 159 days
Safer after May 14 (1-in-10 risk)
Possible by Sep 17 (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) | May 2 · May 18 · Jun 14 | Aug 28 · Sep 19 · Oct 5 | 120 days | 100% |
| Frost / freeze (32°F) | Apr 7 · Apr 29 · May 14 | Sep 17 · Oct 2 · Oct 25 | 159 days | 100% |
| Hard freeze (28°F) | Mar 9 · Apr 3 · Apr 27 | Sep 29 · Oct 18 · Nov 15 | 197 days | 100% |
Planting calendar for Colton
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 12 |
| 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 22 |
| Summer squash | Sow outdoors | May 15 – Jun 29 |
| Winter squash & pumpkins | Sow outdoors | May 29 – Jun 29 |
| Snap beans | Sow outdoors | May 15 – Jul 15 |
| Sweet corn | Sow outdoors | May 15 – Jun 12 |
| 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 2 – Jun 12 |
| Broccoli | Transplant outdoors (fall) | Jul 2 – Jul 13 |
| Cabbage | Start seeds indoors (spring) | Mar 1 – Mar 29 |
| Cabbage | Transplant outdoors (spring) | Mar 29 – Apr 29 |
| Cabbage | Start seeds indoors (fall) | May 23 – Jun 22 |
| Cabbage | Transplant outdoors (fall) | Jun 22 – Jul 23 |
| Leaf lettuce | Sow outdoors (spring) | Mar 29 – Jun 14 |
| Leaf lettuce | Sow outdoors (fall) | Jun 22 – Aug 8 |
| Spinach | Sow outdoors (spring) | Mar 22 – May 5 |
| Spinach | Sow outdoors (fall) | Jul 9 – Aug 13 |
| Radishes | Sow outdoors (spring) | Mar 29 – May 19 |
| Radishes | Sow outdoors (fall) | Jun 22 – Aug 23 |
| Kale | Sow outdoors (spring) | Apr 15 – May 5 |
| Kale | Sow outdoors (fall) | Jun 15 – Jul 23 |
| Carrots | Sow outdoors (spring) | Apr 29 – Jun 14 |
| Carrots | Sow outdoors (fall) | May 23 – Jul 8 |
| Garlic | Plant outdoors (fall) | Sep 22 – Oct 23 |
Where these dates come from
ZIP code 99113 is matched to the NOAA station Pullman Moscow Rgnl Ap, WA, 17.7 km away, at 2,551 ft elevation (28 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Pullman Moscow Rgnl Ap, WA (used) | 2,551 ft | Apr 29 | Oct 2 |
| Pullman 2 Nw, WA | 2,515 ft | May 6 | Sep 29 |
| Moscow U Of I, ID | 2,660 ft | — | — |
| Lewiston Nez Perce Co Ap, ID | 1,436 ft | Apr 6 | Oct 26 |
Frost dates near Colton
- Uniontown, WA 99179 · last —, first —
- Pullman, WA 99164 · last May 6, first Sep 29
- Genesee, ID 83832 · last —, first —
- Moscow, ID 83844 · last —, first —
- Clarkston, WA 99403 · last Apr 6, first Oct 26
- Albion, WA 99102 · last May 6, first Sep 29
- Viola, ID 83872 · last May 15, first Sep 21
- Lewiston, ID 83501 · last Apr 6, first Oct 26
Frequently asked questions
- When is the last frost in Colton, WA?
- For ZIP code 99113, the average last spring frost (32°F) is April 29, based on NOAA 1991-2020 climate normals for the Pullman Moscow Rgnl Ap, WA weather station. There is a 1-in-10 chance of a frost after May 14.
- When is the first frost in Colton, WA?
- The average first fall frost (32°F) is October 2. There is a 1-in-10 chance of frost by September 17, so tender plants are at risk from that point on.
- How long is the growing season in 99113?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 159 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.