Frost Dates for Richland, WA
In Richland, WA, the average last spring frost is around Apr 6 and the average first fall frost around Oct 24, for a growing season of about 200 days. For frost-tender plants, wait until Apr 24, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Richland, WA weather station, 2 miles away, elevation 373 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% | Apr 24 | Oct 10 |
| 20% | Apr 17 | Oct 14 |
| 30% | Apr 13 | Oct 18 |
| 40% | Apr 10 | Oct 21 |
| 50% | Apr 6 | Oct 24 |
| 60% | Apr 3 | Oct 26 |
| 70% | Mar 31 | Oct 30 |
| 80% | Mar 28 | Nov 3 |
| 90% | Mar 22 | Nov 8 |
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) | Apr 25 | Oct 14 |
| Frost / freeze (32°F) | Apr 6 | Oct 24 |
| Hard freeze (28°F) | Mar 18 | Nov 4 |
Planting calendar for Richland
Transplant Apr 13 – Apr 27
Transplant Apr 20 – May 4
Transplant Apr 20 – May 4
Transplant Apr 13 – Apr 27
Sow or transplant Apr 13 – Apr 27
Sow or transplant Apr 13 – Apr 27
Sow or transplant Apr 20 – May 4
Sow or transplant Mar 9 – Mar 23
Fall sowing Aug 29 – Sep 26
Fall sowing Aug 29 – Sep 19
Fall sowing Aug 15 – Aug 29
Sow or transplant Mar 9 – Mar 23
Fall sowing Aug 15 – Sep 12
Transplant Mar 23 – Apr 6
Fall sowing Aug 1 – Aug 15
Transplant Mar 16 – Mar 30
Fall sowing Aug 1 – Aug 15
Fall sowing Aug 1 – Aug 15
Fall sowing Sep 12 – Oct 3
Fall sowing Aug 15 – Aug 29
Plant Mar 9 – Mar 23
Based on the average last frost (Apr 6) and first frost (Oct 24). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.