Frost dates for 98267Marblemount, WA
The average last spring frost in Marblemount is April 8 and the average first fall frost is November 10, giving a typical growing season of about 214 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 8
- Average first fall frost
- Nov 10
- Growing season
- 214 days
Safer after Apr 30 (1-in-10 risk)
Possible by Oct 26 (1-in-10 risk)
First frost typically in 16 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 15 · Apr 30 · May 14 | Oct 14 · Oct 26 · Nov 10 | 178 days | 100% |
| Frost / freeze (32°F) | Mar 16 · Apr 8 · Apr 30 | Oct 26 · Nov 10 · Nov 25 | 214 days | 100% |
| Hard freeze (28°F) | Feb 19 · Mar 11 · Mar 31 | Nov 6 · Nov 25 · Dec 17 | 257 days | 100% |
Planting calendar for Marblemount
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 8 – May 14 |
| Tomatoes | Transplant outdoors | Apr 24 – Jul 21 |
| Peppers | Start seeds indoors | Mar 8 – Apr 8 |
| Peppers | Transplant outdoors | May 8 – Jun 8 |
| Eggplant | Start seeds indoors | Mar 25 – Apr 23 |
| Eggplant | Transplant outdoors | May 8 – Jun 8 |
| Cucumbers | Sow outdoors | May 8 – Jul 31 |
| Summer squash | Sow outdoors | Apr 24 – Jun 8 |
| Winter squash & pumpkins | Sow outdoors | May 8 – Jun 8 |
| Snap beans | Sow outdoors | Apr 24 – Aug 23 |
| Sweet corn | Sow outdoors | Apr 24 – Jul 21 |
| Watermelon & cantaloupe | Sow outdoors | May 8 – Jun 8 |
| Okra | Sow outdoors | May 1 – May 24 |
| Peas | Sow outdoors (spring) | Mar 8 – Apr 23 |
| Potatoes | Plant outdoors (spring) | Mar 8 – May 8 |
| Onions | Start seeds indoors (spring) | Jan 25 – Feb 21 |
| Onions | Transplant outdoors (spring) | Mar 25 – Apr 23 |
| Broccoli | Start seeds indoors (spring) | Feb 18 – Mar 24 |
| Broccoli | Transplant outdoors (spring) | Mar 25 – Apr 23 |
| Broccoli | Start seeds indoors (fall) | Jul 11 – Jul 21 |
| Broccoli | Transplant outdoors (fall) | Aug 10 – Aug 21 |
| Cabbage | Start seeds indoors (spring) | Feb 8 – Mar 8 |
| Cabbage | Transplant outdoors (spring) | Mar 8 – Apr 8 |
| Cabbage | Start seeds indoors (fall) | Jul 1 – Jul 31 |
| Cabbage | Transplant outdoors (fall) | Jul 31 – Aug 31 |
| Leaf lettuce | Sow outdoors (spring) | Mar 8 – May 24 |
| Leaf lettuce | Sow outdoors (fall) | Jul 31 – Sep 16 |
| Spinach | Sow outdoors (spring) | Mar 1 – Apr 14 |
| Spinach | Sow outdoors (fall) | Aug 17 – Sep 21 |
| Radishes | Sow outdoors (spring) | Mar 8 – Apr 28 |
| Radishes | Sow outdoors (fall) | Jul 31 – Oct 1 |
| Kale | Sow outdoors (spring) | Mar 25 – Apr 14 |
| Kale | Sow outdoors (fall) | Jul 24 – Aug 31 |
| Carrots | Sow outdoors (spring) | Apr 8 – May 24 |
| Carrots | Sow outdoors (fall) | Jul 1 – Aug 16 |
| Garlic | Plant outdoors (fall) | Oct 31 – Dec 1 |
Where these dates come from
ZIP code 98267 is matched to the NOAA station Ross Dam, WA, 36.3 km away, at 1,236 ft elevation (4,840 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Ross Dam, WA (used) | 1,236 ft | Apr 8 | Nov 10 |
| Darrington 21 Nne, WA | 407 ft | Apr 16 | Oct 25 |
| Newhalem, WA | 525 ft | Apr 2 | Nov 14 |
| Darrington Rs, WA | 550 ft | Apr 16 | Oct 23 |
Frost dates near Marblemount
- Rockport, WA 98283 · last Apr 16, first Oct 25
- Concrete, WA 98237 · last Apr 24, first Oct 29
- Darrington, WA 98241 · last Apr 16, first Oct 23
- Hamilton, WA 98255 · last Mar 27, first Nov 6
- Stehekin, WA 98852 · last Apr 27, first Oct 17
- Lyman, WA 98263 · last Mar 27, first Nov 6
- Mount Vernon, WA 98274 · last Mar 27, first Nov 6
- Granite Falls, WA 98252 · last Mar 9, first Nov 17
Frequently asked questions
- When is the last frost in Marblemount, WA?
- For ZIP code 98267, the average last spring frost (32°F) is April 8, based on NOAA 1991-2020 climate normals for the Ross Dam, WA weather station. There is a 1-in-10 chance of a frost after April 30.
- When is the first frost in Marblemount, WA?
- The average first fall frost (32°F) is November 10. There is a 1-in-10 chance of frost by October 26, so tender plants are at risk from that point on.
- How long is the growing season in 98267?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 214 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.