Frost dates for 98948Toppenish, WA
The average last spring frost in Toppenish is April 21 and the average first fall frost is October 15, giving a typical growing season of about 176 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 21
- Average first fall frost
- Oct 15
- Growing season
- 176 days
Safer after May 7 (1-in-10 risk)
Possible by Oct 4 (1-in-10 risk)
Last frost typically in 169 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 22 · May 6 · May 25 | Sep 25 · Oct 5 · Oct 16 | 150 days | 100% |
| Frost / freeze (32°F) | Apr 1 · Apr 21 · May 7 | Oct 4 · Oct 15 · Oct 27 | 176 days | 100% |
| Hard freeze (28°F) | Mar 10 · Mar 31 · Apr 21 | Oct 13 · Oct 26 · Nov 9 | 210 days | 100% |
Planting calendar for Toppenish
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 21 – May 27 |
| Tomatoes | Transplant outdoors | May 7 – Jun 25 |
| Peppers | Start seeds indoors | Mar 21 – Apr 21 |
| Peppers | Transplant outdoors | May 21 – Jun 21 |
| Eggplant | Start seeds indoors | Apr 7 – May 6 |
| Eggplant | Transplant outdoors | May 21 – Jun 21 |
| Cucumbers | Sow outdoors | May 21 – Jul 5 |
| Summer squash | Sow outdoors | May 7 – Jun 21 |
| Winter squash & pumpkins | Sow outdoors | May 21 – Jun 21 |
| Snap beans | Sow outdoors | May 7 – Jul 28 |
| Sweet corn | Sow outdoors | May 7 – Jun 25 |
| Watermelon & cantaloupe | Sow outdoors | May 21 – Jun 21 |
| Okra | Sow outdoors | May 14 – Jun 6 |
| Peas | Sow outdoors (spring) | Mar 21 – May 6 |
| Potatoes | Plant outdoors (spring) | Mar 21 – May 21 |
| Onions | Start seeds indoors (spring) | Feb 7 – Mar 6 |
| Onions | Transplant outdoors (spring) | Apr 7 – May 6 |
| Broccoli | Start seeds indoors (spring) | Mar 3 – Apr 6 |
| Broccoli | Transplant outdoors (spring) | Apr 7 – May 6 |
| Broccoli | Start seeds indoors (fall) | Jun 15 – Jun 25 |
| Broccoli | Transplant outdoors (fall) | Jul 15 – Jul 26 |
| Cabbage | Start seeds indoors (spring) | Feb 21 – Mar 21 |
| Cabbage | Transplant outdoors (spring) | Mar 21 – Apr 21 |
| Cabbage | Start seeds indoors (fall) | Jun 5 – Jul 5 |
| Cabbage | Transplant outdoors (fall) | Jul 5 – Aug 5 |
| Leaf lettuce | Sow outdoors (spring) | Mar 21 – Jun 6 |
| Leaf lettuce | Sow outdoors (fall) | Jul 5 – Aug 21 |
| Spinach | Sow outdoors (spring) | Mar 14 – Apr 27 |
| Spinach | Sow outdoors (fall) | Jul 22 – Aug 26 |
| Radishes | Sow outdoors (spring) | Mar 21 – May 11 |
| Radishes | Sow outdoors (fall) | Jul 5 – Sep 5 |
| Kale | Sow outdoors (spring) | Apr 7 – Apr 27 |
| Kale | Sow outdoors (fall) | Jun 28 – Aug 5 |
| Carrots | Sow outdoors (spring) | Apr 21 – Jun 6 |
| Carrots | Sow outdoors (fall) | Jun 5 – Jul 21 |
| Garlic | Plant outdoors (fall) | Oct 5 – Nov 5 |
Where these dates come from
ZIP code 98948 is matched to the NOAA station Wapato, WA, 9.6 km away, at 841 ft elevation (80 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Wapato, WA (used) | 841 ft | Apr 21 | Oct 15 |
| Moxee City 10 E, WA | 1,550 ft | May 4 | Oct 10 |
| Sunnyside #2, WA | 805 ft | Apr 30 | Oct 8 |
| Sunnyside, WA | 747 ft | May 1 | Oct 6 |
Frost dates near Toppenish
- Buena, WA 98921 · last Apr 21, first Oct 15
- Zillah, WA 98953 · last Apr 21, first Oct 15
- Wapato, WA 98951 · last Apr 21, first Oct 15
- Granger, WA 98932 · last May 1, first Oct 6
- Parker, WA 98939 · last Apr 21, first Oct 15
- Outlook, WA 98938 · last May 1, first Oct 6
- Harrah, WA 98933 · last Apr 21, first Oct 15
- Moxee, WA 98936 · last May 8, first Oct 4
Frequently asked questions
- When is the last frost in Toppenish, WA?
- For ZIP code 98948, the average last spring frost (32°F) is April 21, based on NOAA 1991-2020 climate normals for the Wapato, WA weather station. There is a 1-in-10 chance of a frost after May 7.
- When is the first frost in Toppenish, WA?
- The average first fall frost (32°F) is October 15. There is a 1-in-10 chance of frost by October 4, so tender plants are at risk from that point on.
- How long is the growing season in 98948?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 176 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.