Frost dates for 98290Snohomish, WA
The average last spring frost in Snohomish is April 17 and the average first fall frost is October 23, giving a typical growing season of about 188 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 17
- Average first fall frost
- Oct 23
- Growing season
- 188 days
Safer after May 7 (1-in-10 risk)
Possible by Oct 7 (1-in-10 risk)
Last frost typically in 173 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 20 · May 5 · May 20 | Sep 21 · Oct 6 · Oct 25 | 153 days | 100% |
| Frost / freeze (32°F) | Mar 29 · Apr 17 · May 7 | Oct 7 · Oct 23 · Nov 9 | 188 days | 100% |
| Hard freeze (28°F) | Mar 6 · Mar 26 · Apr 14 | Oct 20 · Nov 8 · Nov 26 | 225 days | 100% |
Planting calendar for Snohomish
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 3 |
| 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 13 |
| Summer squash | Sow outdoors | May 3 – Jun 17 |
| Winter squash & pumpkins | Sow outdoors | May 17 – Jun 17 |
| Snap beans | Sow outdoors | May 3 – Aug 5 |
| Sweet corn | Sow outdoors | May 3 – Jul 3 |
| 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 23 – Jul 3 |
| Broccoli | Transplant outdoors (fall) | Jul 23 – Aug 3 |
| Cabbage | Start seeds indoors (spring) | Feb 17 – Mar 17 |
| Cabbage | Transplant outdoors (spring) | Mar 17 – Apr 17 |
| Cabbage | Start seeds indoors (fall) | Jun 13 – Jul 13 |
| Cabbage | Transplant outdoors (fall) | Jul 13 – Aug 13 |
| Leaf lettuce | Sow outdoors (spring) | Mar 17 – Jun 2 |
| Leaf lettuce | Sow outdoors (fall) | Jul 13 – Aug 29 |
| Spinach | Sow outdoors (spring) | Mar 10 – Apr 23 |
| Spinach | Sow outdoors (fall) | Jul 30 – Sep 3 |
| Radishes | Sow outdoors (spring) | Mar 17 – May 7 |
| Radishes | Sow outdoors (fall) | Jul 13 – Sep 13 |
| Kale | Sow outdoors (spring) | Apr 3 – Apr 23 |
| Kale | Sow outdoors (fall) | Jul 6 – Aug 13 |
| Carrots | Sow outdoors (spring) | Apr 17 – Jun 2 |
| Carrots | Sow outdoors (fall) | Jun 13 – Jul 29 |
| Garlic | Plant outdoors (fall) | Oct 13 – Nov 13 |
Where these dates come from
ZIP code 98290 is matched to the NOAA station Monroe, WA, 8 km away, at 120 ft elevation (107 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Monroe, WA (used) | 120 ft | Apr 17 | Oct 23 |
| Everett, WA | 60 ft | Mar 24 | Nov 2 |
| Everett Snohomish Ap, WA | 606 ft | Mar 9 | Nov 17 |
| Startup 1 E, WA | 170 ft | Apr 15 | Oct 25 |
Frost dates near Snohomish
- Snohomish, WA 98291 · last Apr 17, first Oct 23
- Everett, WA 98208 · last Mar 9, first Nov 17
- Monroe, WA 98272 · last Apr 17, first Oct 23
- Mill Creek, WA 98082 · last Mar 9, first Nov 17
- Bothell, WA 98012 · last Mar 9, first Nov 17
- Lake Stevens, WA 98258 · last Mar 24, first Nov 2
- Lynnwood, WA 98087 · last Mar 9, first Nov 17
- Woodinville, WA 98072 · last Mar 9, first Nov 17
Frequently asked questions
- When is the last frost in Snohomish, WA?
- For ZIP code 98290, the average last spring frost (32°F) is April 17, based on NOAA 1991-2020 climate normals for the Monroe, WA weather station. There is a 1-in-10 chance of a frost after May 7.
- When is the first frost in Snohomish, WA?
- The average first fall frost (32°F) is October 23. There is a 1-in-10 chance of frost by October 7, so tender plants are at risk from that point on.
- How long is the growing season in 98290?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 188 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.