Frost Dates for Pullman, WA
In Pullman, WA, the average last spring frost is around May 6 and the average first fall frost around Sep 29, for a growing season of about 143 days. For frost-tender plants, wait until May 25, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Pullman 2 Nw, WA weather station, 2 miles away, elevation 2,515 ft. Frost can come earlier in low spots and valleys and later near cities and large lakes.
Frost probability by date
Chance of a 32°F frost after the spring date, or before the fall date.
| Chance | Last spring frost | First fall frost |
|---|---|---|
| 10% | May 25 | Sep 9 |
| 20% | May 18 | Sep 16 |
| 30% | May 13 | Sep 22 |
| 40% | May 10 | Sep 27 |
| 50% | May 6 | Sep 29 |
| 60% | May 3 | Oct 2 |
| 70% | Apr 30 | Oct 5 |
| 80% | Apr 27 | Oct 9 |
| 90% | Apr 22 | Oct 15 |
Light frost vs. hard freeze
Average (50%) dates for each temperature. Tender plants are damaged at 36°F; most hardy crops survive until 28°F.
| Temperature | Last in spring | First in fall |
|---|---|---|
| Light frost (36°F) | Jun 1 | Sep 11 |
| Frost / freeze (32°F) | May 6 | Sep 29 |
| Hard freeze (28°F) | Apr 19 | Oct 12 |
Planting calendar for Pullman
Transplant May 13 – May 27
Transplant May 20 – Jun 3
Transplant May 20 – Jun 3
Transplant May 13 – May 27
Sow or transplant May 13 – May 27
Sow or transplant May 13 – May 27
Sow or transplant May 20 – Jun 3
Sow or transplant Apr 8 – Apr 22
Fall sowing Aug 4 – Sep 1
Fall sowing Aug 4 – Aug 25
Fall sowing Jul 21 – Aug 4
Sow or transplant Apr 8 – Apr 22
Fall sowing Jul 21 – Aug 18
Transplant Apr 22 – May 6
Fall sowing Jul 7 – Jul 21
Transplant Apr 15 – Apr 29
Fall sowing Jul 7 – Jul 21
Fall sowing Jul 7 – Jul 21
Fall sowing Aug 18 – Sep 8
Fall sowing Jul 21 – Aug 4
Plant Apr 8 – Apr 22
Based on the average last frost (May 6) and first frost (Sep 29). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.