Frost dates for 97339Corvallis, OR
The average last spring frost in Corvallis is April 17 and the average first fall frost is October 28, giving a typical growing season of about 194 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 17
- Average first fall frost
- Oct 28
- Growing season
- 194 days
Safer after May 8 (1-in-10 risk)
Possible by Oct 5 (1-in-10 risk)
Last frost typically in 167 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 25 · May 11 · Jun 2 | Sep 23 · Oct 10 · Oct 28 | 151 days | 100% |
| Frost / freeze (32°F) | Mar 22 · Apr 17 · May 8 | Oct 5 · Oct 28 · Nov 19 | 194 days | 100% |
| Hard freeze (28°F) | Jan 25 · Mar 1 · Apr 5 | Oct 22 · Nov 17 · Dec 18 | 259 days | 100% |
Planting calendar for Corvallis
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 17 – May 23 |
| Tomatoes | Transplant outdoors | May 3 – Jul 8 |
| Peppers | Start seeds indoors | Mar 17 – Apr 17 |
| Peppers | Transplant outdoors | May 17 – Jun 17 |
| Eggplant | Start seeds indoors | Apr 3 – May 2 |
| Eggplant | Transplant outdoors | May 17 – Jun 17 |
| Cucumbers | Sow outdoors | May 17 – Jul 18 |
| Summer squash | Sow outdoors | May 3 – Jun 17 |
| Winter squash & pumpkins | Sow outdoors | May 17 – Jun 17 |
| Snap beans | Sow outdoors | May 3 – Aug 10 |
| Sweet corn | Sow outdoors | May 3 – Jul 8 |
| Watermelon & cantaloupe | Sow outdoors | May 17 – Jun 17 |
| Okra | Sow outdoors | May 10 – Jun 2 |
| Peas | Sow outdoors (spring) | Mar 17 – May 2 |
| Potatoes | Plant outdoors (spring) | Mar 17 – May 17 |
| Onions | Start seeds indoors (spring) | Feb 3 – Mar 2 |
| Onions | Transplant outdoors (spring) | Apr 3 – May 2 |
| Broccoli | Start seeds indoors (spring) | Feb 27 – Apr 2 |
| Broccoli | Transplant outdoors (spring) | Apr 3 – May 2 |
| Broccoli | Start seeds indoors (fall) | Jun 28 – Jul 8 |
| Broccoli | Transplant outdoors (fall) | Jul 28 – Aug 8 |
| Cabbage | Start seeds indoors (spring) | Feb 17 – Mar 17 |
| Cabbage | Transplant outdoors (spring) | Mar 17 – Apr 17 |
| Cabbage | Start seeds indoors (fall) | Jun 18 – Jul 18 |
| Cabbage | Transplant outdoors (fall) | Jul 18 – Aug 18 |
| Leaf lettuce | Sow outdoors (spring) | Mar 17 – Jun 2 |
| Leaf lettuce | Sow outdoors (fall) | Jul 18 – Sep 3 |
| Spinach | Sow outdoors (spring) | Mar 10 – Apr 23 |
| Spinach | Sow outdoors (fall) | Aug 4 – Sep 8 |
| Radishes | Sow outdoors (spring) | Mar 17 – May 7 |
| Radishes | Sow outdoors (fall) | Jul 18 – Sep 18 |
| Kale | Sow outdoors (spring) | Apr 3 – Apr 23 |
| Kale | Sow outdoors (fall) | Jul 11 – Aug 18 |
| Carrots | Sow outdoors (spring) | Apr 17 – Jun 2 |
| Carrots | Sow outdoors (fall) | Jun 18 – Aug 3 |
| Garlic | Plant outdoors (fall) | Oct 18 – Nov 18 |
Where these dates come from
ZIP code 97339 is matched to the NOAA station Corvallis State Univ, OR, 9.6 km away, at 225 ft elevation (5 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Corvallis State Univ, OR (used) | 225 ft | Apr 17 | Oct 28 |
| Corvallis Water Bureau, OR | 592 ft | May 15 | Oct 8 |
| Corvallis 10 Ssw, OR | 312 ft | Apr 11 | Oct 30 |
| Lebanon, OR | 330 ft | Mar 14 | Nov 18 |
Frost dates near Corvallis
- Corvallis, OR 97331 · last Apr 17, first Oct 28
- Philomath, OR 97370 · last May 15, first Oct 8
- Tangent, OR 97389 · last Apr 17, first Oct 28
- Albany, OR 97321 · last Apr 17, first Oct 28
- Shedd, OR 97377 · last Apr 17, first Oct 28
- Halsey, OR 97348 · last Apr 17, first Oct 28
- Monroe, OR 97456 · last Apr 11, first Oct 23
- Blodgett, OR 97326 · last May 15, first Oct 8
Frequently asked questions
- When is the last frost in Corvallis, OR?
- For ZIP code 97339, the average last spring frost (32°F) is April 17, based on NOAA 1991-2020 climate normals for the Corvallis State Univ, OR weather station. There is a 1-in-10 chance of a frost after May 8.
- When is the first frost in Corvallis, OR?
- The average first fall frost (32°F) is October 28. There is a 1-in-10 chance of frost by October 5, so tender plants are at risk from that point on.
- How long is the growing season in 97339?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 194 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.