Frost dates for 98858Waterville, WA
The average last spring frost in Waterville is May 14 and the average first fall frost is October 1, giving a typical growing season of about 140 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 14
- Average first fall frost
- Oct 1
- Growing season
- 140 days
Safer after Jun 4 (1-in-10 risk)
Possible by Sep 18 (1-in-10 risk)
Last frost typically in 200 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) | May 16 · Jun 6 · Jun 27 | Sep 2 · Sep 19 · Sep 30 | 105 days | 100% |
| Frost / freeze (32°F) | Apr 28 · May 14 · Jun 4 | Sep 18 · Oct 1 · Oct 14 | 140 days | 100% |
| Hard freeze (28°F) | Apr 15 · Apr 29 · May 15 | Sep 30 · Oct 12 · Oct 25 | 164 days | 100% |
Planting calendar for Waterville
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 | Apr 13 – Jun 19 |
| Tomatoes | Transplant outdoors | May 30 – Jun 11 |
| Peppers | Start seeds indoors | Apr 13 – May 14 |
| Peppers | Transplant outdoors | Jun 13 – Jul 14 |
| Eggplant | Start seeds indoors | Apr 30 – May 29 |
| Eggplant | Transplant outdoors | Jun 13 – Jul 14 |
| Cucumbers | Sow outdoors | Jun 13 – Jun 21 |
| Summer squash | Sow outdoors | May 30 – Jul 14 |
| Winter squash & pumpkins | Sow outdoors | Jun 13 – Jul 14 |
| Snap beans | Sow outdoors | May 30 – Jul 14 |
| Sweet corn | Sow outdoors | May 30 – Jun 11 |
| Watermelon & cantaloupe | Sow outdoors | Jun 13 – Jul 14 |
| Okra | Sow outdoors | Jun 6 – Jun 29 |
| Peas | Sow outdoors (spring) | Apr 13 – May 29 |
| Potatoes | Plant outdoors (spring) | Apr 13 – Jun 13 |
| Onions | Start seeds indoors (spring) | Mar 2 – Mar 29 |
| Onions | Transplant outdoors (spring) | Apr 30 – May 29 |
| Broccoli | Start seeds indoors (spring) | Mar 26 – Apr 29 |
| Broccoli | Transplant outdoors (spring) | Apr 30 – May 29 |
| Broccoli | Start seeds indoors (fall) | Jun 1 – Jun 11 |
| Broccoli | Transplant outdoors (fall) | Jul 1 – Jul 12 |
| Cabbage | Start seeds indoors (spring) | Mar 16 – Apr 13 |
| Cabbage | Transplant outdoors (spring) | Apr 13 – May 14 |
| Cabbage | Start seeds indoors (fall) | May 22 – Jun 21 |
| Cabbage | Transplant outdoors (fall) | Jun 21 – Jul 22 |
| Leaf lettuce | Sow outdoors (spring) | Apr 13 – Jun 29 |
| Leaf lettuce | Sow outdoors (fall) | Jun 21 – Aug 7 |
| Spinach | Sow outdoors (spring) | Apr 6 – May 20 |
| Spinach | Sow outdoors (fall) | Jul 8 – Aug 12 |
| Radishes | Sow outdoors (spring) | Apr 13 – Jun 3 |
| Radishes | Sow outdoors (fall) | Jun 21 – Aug 22 |
| Kale | Sow outdoors (spring) | Apr 30 – May 20 |
| Kale | Sow outdoors (fall) | Jun 14 – Jul 22 |
| Carrots | Sow outdoors (spring) | May 14 – Jun 29 |
| Carrots | Sow outdoors (fall) | May 22 – Jul 7 |
| Garlic | Plant outdoors (fall) | Sep 21 – Oct 22 |
Where these dates come from
ZIP code 98858 is matched to the NOAA station Waterville, WA, 7.2 km away, at 2,664 ft elevation (108 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Waterville, WA (used) | 2,664 ft | May 14 | Oct 1 |
| Chelan, WA | 1,194 ft | Apr 17 | Oct 22 |
| Entiat Fish Hatchery, WA | 1,027 ft | Apr 5 | Oct 24 |
| Wenatchee Pangborn Ap, WA | 1,229 ft | Apr 8 | Oct 24 |
Frost dates near Waterville
- Orondo, WA 98843 · last May 22, first Sep 22
- Chelan Falls, WA 98817 · last Apr 17, first Oct 22
- Entiat, WA 98822 · last May 14, first Oct 1
- Palisades, WA 98845 · last Apr 8, first Oct 24
- Chelan, WA 98816 · last Apr 17, first Oct 22
- Ardenvoir, WA 98811 · last Apr 5, first Oct 24
- Rock Island, WA 98850 · last Apr 4, first Oct 28
- East Wenatchee, WA 98802 · last Apr 4, first Oct 28
Frequently asked questions
- When is the last frost in Waterville, WA?
- For ZIP code 98858, the average last spring frost (32°F) is May 14, based on NOAA 1991-2020 climate normals for the Waterville, WA weather station. There is a 1-in-10 chance of a frost after June 4.
- When is the first frost in Waterville, WA?
- The average first fall frost (32°F) is October 1. There is a 1-in-10 chance of frost by September 18, so tender plants are at risk from that point on.
- How long is the growing season in 98858?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 140 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.