Frost Dates for Maple Valley, WA
In Maple Valley, WA, the average last spring frost is around Apr 20 and the average first fall frost around Oct 25, for a growing season of about 187 days. For frost-tender plants, wait until May 10, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Landsburg, WA weather station, 3 miles away, elevation 535 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 10 | Oct 5 |
| 20% | May 4 | Oct 13 |
| 30% | Apr 29 | Oct 17 |
| 40% | Apr 25 | Oct 21 |
| 50% | Apr 20 | Oct 25 |
| 60% | Apr 16 | Oct 29 |
| 70% | Apr 12 | Nov 1 |
| 80% | Apr 6 | Nov 6 |
| 90% | Mar 31 | Nov 12 |
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) | May 10 | Oct 6 |
| Frost / freeze (32°F) | Apr 20 | Oct 25 |
| Hard freeze (28°F) | Mar 24 | Nov 12 |
Planting calendar for Maple Valley
Transplant Apr 27 – May 11
Transplant May 4 – May 18
Transplant May 4 – May 18
Transplant Apr 27 – May 11
Sow or transplant Apr 27 – May 11
Sow or transplant Apr 27 – May 11
Sow or transplant May 4 – May 18
Sow or transplant Mar 23 – Apr 6
Fall sowing Aug 30 – Sep 27
Fall sowing Aug 30 – Sep 20
Fall sowing Aug 16 – Aug 30
Sow or transplant Mar 23 – Apr 6
Fall sowing Aug 16 – Sep 13
Transplant Apr 6 – Apr 20
Fall sowing Aug 2 – Aug 16
Transplant Mar 30 – Apr 13
Fall sowing Aug 2 – Aug 16
Fall sowing Aug 2 – Aug 16
Fall sowing Sep 13 – Oct 4
Fall sowing Aug 16 – Aug 30
Plant Mar 23 – Apr 6
Based on the average last frost (Apr 20) and first frost (Oct 25). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.