Frost Dates for Tualatin, OR
In Tualatin, OR, the average last spring frost is around Apr 1 and the average first fall frost around Nov 6, for a growing season of about 222 days. For frost-tender plants, wait until Apr 26, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Beaverton 2 Ssw, OR weather station, 6 miles away, elevation 270 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 26 | Oct 19 |
| 20% | Apr 18 | Oct 25 |
| 30% | Apr 11 | Oct 29 |
| 40% | Apr 6 | Nov 1 |
| 50% | Apr 1 | Nov 6 |
| 60% | Mar 28 | Nov 11 |
| 70% | Mar 22 | Nov 17 |
| 80% | Mar 15 | Nov 22 |
| 90% | Mar 5 | Dec 1 |
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 28 | Oct 21 |
| Frost / freeze (32°F) | Apr 1 | Nov 6 |
| Hard freeze (28°F) | Feb 26 | Nov 30 |
Planting calendar for Tualatin
Transplant Apr 8 – Apr 22
Transplant Apr 15 – Apr 29
Transplant Apr 15 – Apr 29
Transplant Apr 8 – Apr 22
Sow or transplant Apr 8 – Apr 22
Sow or transplant Apr 8 – Apr 22
Sow or transplant Apr 15 – Apr 29
Sow or transplant Mar 4 – Mar 18
Fall sowing Sep 11 – Oct 9
Fall sowing Sep 11 – Oct 2
Fall sowing Aug 28 – Sep 11
Sow or transplant Mar 4 – Mar 18
Fall sowing Aug 28 – Sep 25
Transplant Mar 18 – Apr 1
Fall sowing Aug 14 – Aug 28
Transplant Mar 11 – Mar 25
Fall sowing Aug 14 – Aug 28
Fall sowing Aug 14 – Aug 28
Fall sowing Sep 25 – Oct 16
Fall sowing Aug 28 – Sep 11
Plant Mar 4 – Mar 18
Based on the average last frost (Apr 1) and first frost (Nov 6). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.