Frost dates for 98237Concrete, WA
The average last spring frost in Concrete is April 24 and the average first fall frost is October 29, giving a typical growing season of about 190 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 24
- Average first fall frost
- Oct 29
- Growing season
- 190 days
Safer after May 9 (1-in-10 risk)
Possible by Oct 12 (1-in-10 risk)
Last frost typically in 172 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 26 · May 11 · May 28 | Sep 28 · Oct 14 · Oct 29 | 154 days | 100% |
| Frost / freeze (32°F) | Apr 4 · Apr 24 · May 9 | Oct 12 · Oct 29 · Nov 17 | 190 days | 100% |
| Hard freeze (28°F) | Mar 5 · Mar 28 · Apr 17 | Oct 23 · Nov 17 · Dec 6 | 234 days | 100% |
Planting calendar for Concrete
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 24 – May 30 |
| Tomatoes | Transplant outdoors | May 10 – Jul 9 |
| Peppers | Start seeds indoors | Mar 24 – Apr 24 |
| Peppers | Transplant outdoors | May 24 – Jun 24 |
| Eggplant | Start seeds indoors | Apr 10 – May 9 |
| Eggplant | Transplant outdoors | May 24 – Jun 24 |
| Cucumbers | Sow outdoors | May 24 – Jul 19 |
| Summer squash | Sow outdoors | May 10 – Jun 24 |
| Winter squash & pumpkins | Sow outdoors | May 24 – Jun 24 |
| Snap beans | Sow outdoors | May 10 – Aug 11 |
| Sweet corn | Sow outdoors | May 10 – Jul 9 |
| Watermelon & cantaloupe | Sow outdoors | May 24 – Jun 24 |
| Okra | Sow outdoors | May 17 – Jun 9 |
| Peas | Sow outdoors (spring) | Mar 24 – May 9 |
| Potatoes | Plant outdoors (spring) | Mar 24 – May 24 |
| Onions | Start seeds indoors (spring) | Feb 10 – Mar 9 |
| Onions | Transplant outdoors (spring) | Apr 10 – May 9 |
| Broccoli | Start seeds indoors (spring) | Mar 6 – Apr 9 |
| Broccoli | Transplant outdoors (spring) | Apr 10 – May 9 |
| Broccoli | Start seeds indoors (fall) | Jun 29 – Jul 9 |
| Broccoli | Transplant outdoors (fall) | Jul 29 – Aug 9 |
| Cabbage | Start seeds indoors (spring) | Feb 24 – Mar 24 |
| Cabbage | Transplant outdoors (spring) | Mar 24 – Apr 24 |
| Cabbage | Start seeds indoors (fall) | Jun 19 – Jul 19 |
| Cabbage | Transplant outdoors (fall) | Jul 19 – Aug 19 |
| Leaf lettuce | Sow outdoors (spring) | Mar 24 – Jun 9 |
| Leaf lettuce | Sow outdoors (fall) | Jul 19 – Sep 4 |
| Spinach | Sow outdoors (spring) | Mar 17 – Apr 30 |
| Spinach | Sow outdoors (fall) | Aug 5 – Sep 9 |
| Radishes | Sow outdoors (spring) | Mar 24 – May 14 |
| Radishes | Sow outdoors (fall) | Jul 19 – Sep 19 |
| Kale | Sow outdoors (spring) | Apr 10 – Apr 30 |
| Kale | Sow outdoors (fall) | Jul 12 – Aug 19 |
| Carrots | Sow outdoors (spring) | Apr 24 – Jun 9 |
| Carrots | Sow outdoors (fall) | Jun 19 – Aug 4 |
| Garlic | Plant outdoors (fall) | Oct 19 – Nov 19 |
Where these dates come from
ZIP code 98237 is matched to the NOAA station Upper Baker Dam, WA, 13.7 km away, at 690 ft elevation (1,413 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Upper Baker Dam, WA (used) | 690 ft | Apr 24 | Oct 29 |
| Concrete Ppl Fish Stn, WA | 195 ft | Mar 28 | Nov 14 |
| Darrington 21 Nne, WA | 407 ft | Apr 16 | Oct 25 |
| Darrington Rs, WA | 550 ft | Apr 16 | Oct 23 |
Frost dates near Concrete
- Rockport, WA 98283 · last Apr 16, first Oct 25
- Hamilton, WA 98255 · last Mar 27, first Nov 6
- Marblemount, WA 98267 · last Apr 8, first Nov 10
- Lyman, WA 98263 · last Mar 27, first Nov 6
- Darrington, WA 98241 · last Apr 16, first Oct 23
- Mount Vernon, WA 98274 · last Mar 27, first Nov 6
- Sedro Woolley, WA 98284 · last Mar 27, first Nov 6
- Acme, WA 98220 · last Mar 27, first Nov 6
Frequently asked questions
- When is the last frost in Concrete, WA?
- For ZIP code 98237, the average last spring frost (32°F) is April 24, based on NOAA 1991-2020 climate normals for the Upper Baker Dam, WA weather station. There is a 1-in-10 chance of a frost after May 9.
- When is the first frost in Concrete, WA?
- The average first fall frost (32°F) is October 29. There is a 1-in-10 chance of frost by October 12, so tender plants are at risk from that point on.
- How long is the growing season in 98237?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 190 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.