Frost Dates for Forest Grove, OR
In Forest Grove, OR, the average last spring frost is around Apr 16 and the average first fall frost around Oct 26, for a growing season of about 192 days. For frost-tender plants, wait until May 5, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Forest Grove, OR weather station, under 1 mile away, elevation 180 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 5 | Oct 6 |
| 20% | Apr 30 | Oct 13 |
| 30% | Apr 26 | Oct 18 |
| 40% | Apr 20 | Oct 22 |
| 50% | Apr 16 | Oct 26 |
| 60% | Apr 11 | Oct 30 |
| 70% | Apr 6 | Nov 3 |
| 80% | Apr 1 | Nov 7 |
| 90% | Mar 26 | Nov 14 |
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 4 | Oct 8 |
| Frost / freeze (32°F) | Apr 16 | Oct 26 |
| Hard freeze (28°F) | Mar 19 | Nov 11 |
Planting calendar for Forest Grove
Transplant Apr 23 – May 7
Transplant Apr 30 – May 14
Transplant Apr 30 – May 14
Transplant Apr 23 – May 7
Sow or transplant Apr 23 – May 7
Sow or transplant Apr 23 – May 7
Sow or transplant Apr 30 – May 14
Sow or transplant Mar 19 – Apr 2
Fall sowing Aug 31 – Sep 28
Fall sowing Aug 31 – Sep 21
Fall sowing Aug 17 – Aug 31
Sow or transplant Mar 19 – Apr 2
Fall sowing Aug 17 – Sep 14
Transplant Apr 2 – Apr 16
Fall sowing Aug 3 – Aug 17
Transplant Mar 26 – Apr 9
Fall sowing Aug 3 – Aug 17
Fall sowing Aug 3 – Aug 17
Fall sowing Sep 14 – Oct 5
Fall sowing Aug 17 – Aug 31
Plant Mar 19 – Apr 2
Based on the average last frost (Apr 16) and first frost (Oct 26). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.