Frost dates for 97116Forest Grove, OR
The average last spring frost in Forest Grove is April 16 and the average first fall frost is October 26, giving a typical growing season of about 192 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 16
- Average first fall frost
- Oct 26
- Growing season
- 192 days
Safer after May 5 (1-in-10 risk)
Possible by Oct 6 (1-in-10 risk)
Last frost typically in 168 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Apr 19 · May 4 · May 25 | Sep 24 · Oct 8 · Oct 30 | 155 days | 100% |
| Frost / freeze (32°F) | Mar 26 · Apr 16 · May 5 | Oct 6 · Oct 26 · Nov 14 | 192 days | 100% |
| Hard freeze (28°F) | Feb 21 · Mar 19 · Apr 12 | Oct 23 · Nov 11 · Dec 5 | 236 days | 100% |
Planting calendar for Forest Grove
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Mar 16 – May 22 |
| Tomatoes | Transplant outdoors | May 2 – Jul 6 |
| Peppers | Start seeds indoors | Mar 16 – Apr 16 |
| Peppers | Transplant outdoors | May 16 – Jun 16 |
| Eggplant | Start seeds indoors | Apr 2 – May 1 |
| Eggplant | Transplant outdoors | May 16 – Jun 16 |
| Cucumbers | Sow outdoors | May 16 – Jul 16 |
| Summer squash | Sow outdoors | May 2 – Jun 16 |
| Winter squash & pumpkins | Sow outdoors | May 16 – Jun 16 |
| Snap beans | Sow outdoors | May 2 – Aug 8 |
| Sweet corn | Sow outdoors | May 2 – Jul 6 |
| Watermelon & cantaloupe | Sow outdoors | May 16 – Jun 16 |
| Okra | Sow outdoors | May 9 – Jun 1 |
| Peas | Sow outdoors (spring) | Mar 16 – May 1 |
| Potatoes | Plant outdoors (spring) | Mar 16 – May 16 |
| Onions | Start seeds indoors (spring) | Feb 2 – Mar 1 |
| Onions | Transplant outdoors (spring) | Apr 2 – May 1 |
| Broccoli | Start seeds indoors (spring) | Feb 26 – Apr 1 |
| Broccoli | Transplant outdoors (spring) | Apr 2 – May 1 |
| Broccoli | Start seeds indoors (fall) | Jun 26 – Jul 6 |
| Broccoli | Transplant outdoors (fall) | Jul 26 – Aug 6 |
| Cabbage | Start seeds indoors (spring) | Feb 16 – Mar 16 |
| Cabbage | Transplant outdoors (spring) | Mar 16 – Apr 16 |
| Cabbage | Start seeds indoors (fall) | Jun 16 – Jul 16 |
| Cabbage | Transplant outdoors (fall) | Jul 16 – Aug 16 |
| Leaf lettuce | Sow outdoors (spring) | Mar 16 – Jun 1 |
| Leaf lettuce | Sow outdoors (fall) | Jul 16 – Sep 1 |
| Spinach | Sow outdoors (spring) | Mar 9 – Apr 22 |
| Spinach | Sow outdoors (fall) | Aug 2 – Sep 6 |
| Radishes | Sow outdoors (spring) | Mar 16 – May 6 |
| Radishes | Sow outdoors (fall) | Jul 16 – Sep 16 |
| Kale | Sow outdoors (spring) | Apr 2 – Apr 22 |
| Kale | Sow outdoors (fall) | Jul 9 – Aug 16 |
| Carrots | Sow outdoors (spring) | Apr 16 – Jun 1 |
| Carrots | Sow outdoors (fall) | Jun 16 – Aug 1 |
| Garlic | Plant outdoors (fall) | Oct 16 – Nov 16 |
Where these dates come from
ZIP code 97116 is matched to the NOAA station Forest Grove, OR, 10.2 km away, at 180 ft elevation (0 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Forest Grove, OR (used) | 180 ft | Apr 16 | Oct 26 |
| Portland-Hillsboro Ap, OR | 204 ft | Apr 16 | Oct 23 |
| Nature Park-Beaverton, OR | 185 ft | Feb 11 | Dec 5 |
| Vernonia #2, OR | 625 ft | May 8 | Oct 1 |
Frost dates near Forest Grove
- Gales Creek, OR 97117 · last Apr 16, first Oct 26
- Manning, OR 97125 · last Apr 16, first Oct 26
- Banks, OR 97106 · last Apr 16, first Oct 26
- Cornelius, OR 97113 · last Apr 16, first Oct 26
- North Plains, OR 97133 · last May 8, first Oct 1
- Buxton, OR 97109 · last May 8, first Oct 1
- Gaston, OR 97119 · last Apr 16, first Oct 26
- Timber, OR 97144 · last May 8, first Oct 1
Frequently asked questions
- When is the last frost in Forest Grove, OR?
- For ZIP code 97116, the average last spring frost (32°F) is April 16, based on NOAA 1991-2020 climate normals for the Forest Grove, OR weather station. There is a 1-in-10 chance of a frost after May 5.
- When is the first frost in Forest Grove, OR?
- The average first fall frost (32°F) is October 26. There is a 1-in-10 chance of frost by October 6, so tender plants are at risk from that point on.
- How long is the growing season in 97116?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 192 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.