Frost Dates for Des Moines, WA
In Des Moines, WA, the average last spring frost is around Mar 2 and the average first fall frost around Nov 23, for a growing season of about 266 days. For frost-tender plants, wait until Mar 23, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Seattle Tacoma Intl. Airport, WA weather station, 4 miles away, elevation 370 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% | Mar 23 | Nov 6 |
| 20% | Mar 16 | Nov 11 |
| 30% | Mar 12 | Nov 14 |
| 40% | Mar 7 | Nov 18 |
| 50% | Mar 2 | Nov 23 |
| 60% | Feb 27 | Nov 28 |
| 70% | Feb 22 | Dec 2 |
| 80% | Feb 16 | Dec 7 |
| 90% | Feb 5 | Dec 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) | Mar 31 | Nov 7 |
| Frost / freeze (32°F) | Mar 2 | Nov 23 |
| Hard freeze (28°F) | Feb 4 | Dec 10 |
Planting calendar for Des Moines
Transplant Mar 9 – Mar 23
Transplant Mar 16 – Mar 30
Transplant Mar 16 – Mar 30
Transplant Mar 9 – Mar 23
Sow or transplant Mar 9 – Mar 23
Sow or transplant Mar 9 – Mar 23
Sow or transplant Mar 16 – Mar 30
Sow or transplant Feb 2 – Feb 16
Fall sowing Sep 28 – Oct 26
Fall sowing Sep 28 – Oct 19
Fall sowing Sep 14 – Sep 28
Sow or transplant Feb 2 – Feb 16
Fall sowing Sep 14 – Oct 12
Transplant Feb 16 – Mar 2
Fall sowing Aug 31 – Sep 14
Transplant Feb 9 – Feb 23
Fall sowing Aug 31 – Sep 14
Fall sowing Aug 31 – Sep 14
Fall sowing Oct 12 – Nov 2
Fall sowing Sep 14 – Sep 28
Plant Feb 2 – Feb 16
Based on the average last frost (Mar 2) and first frost (Nov 23). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.