Frost dates for 98837Moses Lake, WA
The average last spring frost in Moses Lake is April 27 and the average first fall frost is October 8, giving a typical growing season of about 165 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 27
- Average first fall frost
- Oct 8
- Growing season
- 165 days
Safer after May 11 (1-in-10 risk)
Possible by Sep 29 (1-in-10 risk)
Last frost typically in 175 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 27 · May 9 · May 23 | Sep 17 · Sep 29 · Oct 10 | 141 days | 100% |
| Frost / freeze (32°F) | Apr 10 · Apr 27 · May 11 | Sep 29 · Oct 8 · Oct 23 | 165 days | 100% |
| Hard freeze (28°F) | Mar 21 · Apr 10 · Apr 30 | Oct 5 · Oct 20 · Nov 5 | 191 days | 100% |
Planting calendar for Moses Lake
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 27 – Jun 2 |
| Tomatoes | Transplant outdoors | May 13 – Jun 18 |
| Peppers | Start seeds indoors | Mar 27 – Apr 27 |
| Peppers | Transplant outdoors | May 27 – Jun 27 |
| Eggplant | Start seeds indoors | Apr 13 – May 12 |
| Eggplant | Transplant outdoors | May 27 – Jun 27 |
| Cucumbers | Sow outdoors | May 27 – Jun 28 |
| Summer squash | Sow outdoors | May 13 – Jun 27 |
| Winter squash & pumpkins | Sow outdoors | May 27 – Jun 27 |
| Snap beans | Sow outdoors | May 13 – Jul 21 |
| Sweet corn | Sow outdoors | May 13 – Jun 18 |
| Watermelon & cantaloupe | Sow outdoors | May 27 – Jun 27 |
| Okra | Sow outdoors | May 20 – Jun 12 |
| Peas | Sow outdoors (spring) | Mar 27 – May 12 |
| Potatoes | Plant outdoors (spring) | Mar 27 – May 27 |
| Onions | Start seeds indoors (spring) | Feb 13 – Mar 12 |
| Onions | Transplant outdoors (spring) | Apr 13 – May 12 |
| Broccoli | Start seeds indoors (spring) | Mar 9 – Apr 12 |
| Broccoli | Transplant outdoors (spring) | Apr 13 – May 12 |
| Broccoli | Start seeds indoors (fall) | Jun 8 – Jun 18 |
| Broccoli | Transplant outdoors (fall) | Jul 8 – Jul 19 |
| Cabbage | Start seeds indoors (spring) | Feb 27 – Mar 27 |
| Cabbage | Transplant outdoors (spring) | Mar 27 – Apr 27 |
| Cabbage | Start seeds indoors (fall) | May 29 – Jun 28 |
| Cabbage | Transplant outdoors (fall) | Jun 28 – Jul 29 |
| Leaf lettuce | Sow outdoors (spring) | Mar 27 – Jun 12 |
| Leaf lettuce | Sow outdoors (fall) | Jun 28 – Aug 14 |
| Spinach | Sow outdoors (spring) | Mar 20 – May 3 |
| Spinach | Sow outdoors (fall) | Jul 15 – Aug 19 |
| Radishes | Sow outdoors (spring) | Mar 27 – May 17 |
| Radishes | Sow outdoors (fall) | Jun 28 – Aug 29 |
| Kale | Sow outdoors (spring) | Apr 13 – May 3 |
| Kale | Sow outdoors (fall) | Jun 21 – Jul 29 |
| Carrots | Sow outdoors (spring) | Apr 27 – Jun 12 |
| Carrots | Sow outdoors (fall) | May 29 – Jul 14 |
| Garlic | Plant outdoors (fall) | Sep 28 – Oct 29 |
Where these dates come from
ZIP code 98837 is matched to the NOAA station Moses Lake Grant Co Ap, WA, 8.2 km away, at 1,196 ft elevation (90 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Moses Lake Grant Co Ap, WA (used) | 1,196 ft | Apr 27 | Oct 8 |
| Ephrata Muni Ap, WA | 1,252 ft | Apr 22 | Oct 17 |
| Quincy, WA | 1,286 ft | Apr 21 | Oct 16 |
| Smyrna, WA | 560 ft | Apr 23 | Oct 12 |
Frost dates near Moses Lake
- Ephrata, WA 98823 · last Apr 22, first Oct 17
- Marlin, WA 98832 · last May 14, first Sep 26
- Warden, WA 98857 · last Apr 27, first Oct 8
- Soap Lake, WA 98851 · last Apr 22, first Oct 17
- Stratford, WA 98853 · last Apr 22, first Oct 17
- Royal City, WA 99357 · last Apr 23, first Oct 12
- Wilson Creek, WA 98860 · last May 2, first Oct 12
- Othello, WA 99344 · last Apr 25, first Oct 15
Frequently asked questions
- When is the last frost in Moses Lake, WA?
- For ZIP code 98837, the average last spring frost (32°F) is April 27, based on NOAA 1991-2020 climate normals for the Moses Lake Grant Co Ap, WA weather station. There is a 1-in-10 chance of a frost after May 11.
- When is the first frost in Moses Lake, WA?
- The average first fall frost (32°F) is October 8. There is a 1-in-10 chance of frost by September 29, so tender plants are at risk from that point on.
- How long is the growing season in 98837?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 165 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.