Frost dates for 99347Pomeroy, WA
The average last spring frost in Pomeroy is May 2 and the average first fall frost is October 4, giving a typical growing season of about 155 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 2
- Average first fall frost
- Oct 4
- Growing season
- 155 days
Safer after May 19 (1-in-10 risk)
Possible by Sep 17 (1-in-10 risk)
Last frost typically in 180 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 3 · May 19 · Jun 8 | Aug 31 · Sep 19 · Oct 5 | 122 days | 100% |
| Frost / freeze (32°F) | Apr 15 · May 2 · May 19 | Sep 17 · Oct 4 · Oct 24 | 155 days | 100% |
| Hard freeze (28°F) | Mar 21 · Apr 11 · May 4 | Oct 2 · Oct 19 · Nov 7 | 189 days | 100% |
Planting calendar for Pomeroy
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 1 – Jun 7 |
| Tomatoes | Transplant outdoors | May 18 – Jun 14 |
| Peppers | Start seeds indoors | Apr 1 – May 2 |
| Peppers | Transplant outdoors | Jun 1 – Jul 2 |
| Eggplant | Start seeds indoors | Apr 18 – May 17 |
| Eggplant | Transplant outdoors | Jun 1 – Jul 2 |
| Cucumbers | Sow outdoors | Jun 1 – Jun 24 |
| Summer squash | Sow outdoors | May 18 – Jul 2 |
| Winter squash & pumpkins | Sow outdoors | Jun 1 – Jul 2 |
| Snap beans | Sow outdoors | May 18 – Jul 17 |
| Sweet corn | Sow outdoors | May 18 – Jun 14 |
| Watermelon & cantaloupe | Sow outdoors | Jun 1 – Jul 2 |
| Okra | Sow outdoors | May 25 – Jun 17 |
| Peas | Sow outdoors (spring) | Apr 1 – May 17 |
| Potatoes | Plant outdoors (spring) | Apr 1 – Jun 1 |
| Onions | Start seeds indoors (spring) | Feb 18 – Mar 17 |
| Onions | Transplant outdoors (spring) | Apr 18 – May 17 |
| Broccoli | Start seeds indoors (spring) | Mar 14 – Apr 17 |
| Broccoli | Transplant outdoors (spring) | Apr 18 – May 17 |
| Broccoli | Start seeds indoors (fall) | Jun 4 – Jun 14 |
| Broccoli | Transplant outdoors (fall) | Jul 4 – Jul 15 |
| Cabbage | Start seeds indoors (spring) | Mar 4 – Apr 1 |
| Cabbage | Transplant outdoors (spring) | Apr 1 – May 2 |
| Cabbage | Start seeds indoors (fall) | May 25 – Jun 24 |
| Cabbage | Transplant outdoors (fall) | Jun 24 – Jul 25 |
| Leaf lettuce | Sow outdoors (spring) | Apr 1 – Jun 17 |
| Leaf lettuce | Sow outdoors (fall) | Jun 24 – Aug 10 |
| Spinach | Sow outdoors (spring) | Mar 25 – May 8 |
| Spinach | Sow outdoors (fall) | Jul 11 – Aug 15 |
| Radishes | Sow outdoors (spring) | Apr 1 – May 22 |
| Radishes | Sow outdoors (fall) | Jun 24 – Aug 25 |
| Kale | Sow outdoors (spring) | Apr 18 – May 8 |
| Kale | Sow outdoors (fall) | Jun 17 – Jul 25 |
| Carrots | Sow outdoors (spring) | May 2 – Jun 17 |
| Carrots | Sow outdoors (fall) | May 25 – Jul 10 |
| Garlic | Plant outdoors (fall) | Sep 24 – Oct 25 |
Where these dates come from
ZIP code 99347 is matched to the NOAA station Pomeroy, WA, 0.9 km away, at 1,934 ft elevation (28 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Pomeroy, WA (used) | 1,934 ft | May 2 | Oct 4 |
| Dayton 1 Wsw, WA | 1,557 ft | Apr 28 | Oct 13 |
| Lacrosse, WA | 1,476 ft | May 13 | Sep 26 |
| Pullman 2 Nw, WA | 2,515 ft | May 6 | Sep 29 |
Frost dates near Pomeroy
- Dayton, WA 99328 · last Apr 28, first Oct 13
- Colton, WA 99113 · last Apr 29, first Oct 2
- Lacrosse, WA 99143 · last May 13, first Sep 26
- Hay, WA 99136 · last May 13, first Sep 26
- Starbuck, WA 99359 · last Apr 28, first Oct 13
- Uniontown, WA 99179 · last —, first —
- Clarkston, WA 99403 · last Apr 6, first Oct 26
- Pullman, WA 99164 · last May 6, first Sep 29
Frequently asked questions
- When is the last frost in Pomeroy, WA?
- For ZIP code 99347, the average last spring frost (32°F) is May 2, based on NOAA 1991-2020 climate normals for the Pomeroy, WA weather station. There is a 1-in-10 chance of a frost after May 19.
- When is the first frost in Pomeroy, WA?
- The average first fall frost (32°F) is October 4. 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 99347?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 155 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.