Frost dates for 97361Monmouth, OR
The average last spring frost in Monmouth is April 16 and the average first fall frost is November 1, giving a typical growing season of about 199 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 16
- Average first fall frost
- Nov 1
- Growing season
- 199 days
Safer after May 5 (1-in-10 risk)
Possible by Oct 13 (1-in-10 risk)
First frost typically in 1 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 6 · May 23 | Sep 29 · Oct 13 · Nov 1 | 159 days | 100% |
| Frost / freeze (32°F) | Mar 21 · Apr 16 · May 5 | Oct 13 · Nov 1 · Nov 22 | 199 days | 100% |
| Hard freeze (28°F) | Feb 2 · Mar 7 · Apr 8 | Oct 31 · Nov 20 · Dec 15 | 258 days | 100% |
Planting calendar for Monmouth
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 12 |
| 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 22 |
| Summer squash | Sow outdoors | May 2 – Jun 16 |
| Winter squash & pumpkins | Sow outdoors | May 16 – Jun 16 |
| Snap beans | Sow outdoors | May 2 – Aug 14 |
| Sweet corn | Sow outdoors | May 2 – Jul 12 |
| 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) | Jul 2 – Jul 12 |
| Broccoli | Transplant outdoors (fall) | Aug 1 – Aug 12 |
| Cabbage | Start seeds indoors (spring) | Feb 16 – Mar 16 |
| Cabbage | Transplant outdoors (spring) | Mar 16 – Apr 16 |
| Cabbage | Start seeds indoors (fall) | Jun 22 – Jul 22 |
| Cabbage | Transplant outdoors (fall) | Jul 22 – Aug 22 |
| Leaf lettuce | Sow outdoors (spring) | Mar 16 – Jun 1 |
| Leaf lettuce | Sow outdoors (fall) | Jul 22 – Sep 7 |
| Spinach | Sow outdoors (spring) | Mar 9 – Apr 22 |
| Spinach | Sow outdoors (fall) | Aug 8 – Sep 12 |
| Radishes | Sow outdoors (spring) | Mar 16 – May 6 |
| Radishes | Sow outdoors (fall) | Jul 22 – Sep 22 |
| Kale | Sow outdoors (spring) | Apr 2 – Apr 22 |
| Kale | Sow outdoors (fall) | Jul 15 – Aug 22 |
| Carrots | Sow outdoors (spring) | Apr 16 – Jun 1 |
| Carrots | Sow outdoors (fall) | Jun 22 – Aug 7 |
| Garlic | Plant outdoors (fall) | Oct 22 – Nov 22 |
Where these dates come from
ZIP code 97361 is matched to the NOAA station Dallas 2 Ne, OR, 12.5 km away, at 290 ft elevation (21 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Dallas 2 Ne, OR (used) | 290 ft | Apr 16 | Nov 1 |
| Falls City 2 Ssw, OR | 690 ft | Apr 18 | Nov 7 |
| Salem Mcnary Fld, OR | 205 ft | Apr 3 | Nov 1 |
| Corvallis State Univ, OR | 225 ft | Apr 17 | Oct 28 |
Frost dates near Monmouth
- Independence, OR 97351 · last Apr 3, first Nov 1
- Dallas, OR 97338 · last Apr 16, first Nov 1
- Falls City, OR 97344 · last Apr 18, first Nov 7
- Salem, OR 97306 · last Apr 3, first Nov 1
- Rickreall, OR 97371 · last Apr 16, first Nov 1
- Jefferson, OR 97352 · last Apr 3, first Nov 1
- Albany, OR 97321 · last Apr 17, first Oct 28
- Turner, OR 97392 · last Apr 3, first Nov 1
Frequently asked questions
- When is the last frost in Monmouth, OR?
- For ZIP code 97361, the average last spring frost (32°F) is April 16, based on NOAA 1991-2020 climate normals for the Dallas 2 Ne, OR weather station. There is a 1-in-10 chance of a frost after May 5.
- When is the first frost in Monmouth, OR?
- The average first fall frost (32°F) is November 1. There is a 1-in-10 chance of frost by October 13, so tender plants are at risk from that point on.
- How long is the growing season in 97361?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 199 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.