Frost dates for 99352Richland, WA
The average last spring frost in Richland is April 6 and the average first fall frost is October 24, giving a typical growing season of about 200 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 6
- Average first fall frost
- Oct 24
- Growing season
- 200 days
Safer after Apr 24 (1-in-10 risk)
Possible by Oct 10 (1-in-10 risk)
Last frost typically in 155 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 11 · Apr 25 · May 8 | Sep 30 · Oct 14 · Oct 27 | 171 days | 100% |
| Frost / freeze (32°F) | Mar 22 · Apr 6 · Apr 24 | Oct 10 · Oct 24 · Nov 8 | 200 days | 100% |
| Hard freeze (28°F) | Mar 1 · Mar 18 · Apr 5 | Oct 20 · Nov 4 · Nov 23 | 229 days | 100% |
Planting calendar for Richland
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 6 – May 12 |
| Tomatoes | Transplant outdoors | Apr 22 – Jul 4 |
| Peppers | Start seeds indoors | Mar 6 – Apr 6 |
| Peppers | Transplant outdoors | May 6 – Jun 6 |
| Eggplant | Start seeds indoors | Mar 23 – Apr 21 |
| Eggplant | Transplant outdoors | May 6 – Jun 6 |
| Cucumbers | Sow outdoors | May 6 – Jul 14 |
| Summer squash | Sow outdoors | Apr 22 – Jun 6 |
| Winter squash & pumpkins | Sow outdoors | May 6 – Jun 6 |
| Snap beans | Sow outdoors | Apr 22 – Aug 6 |
| Sweet corn | Sow outdoors | Apr 22 – Jul 4 |
| Watermelon & cantaloupe | Sow outdoors | May 6 – Jun 6 |
| Okra | Sow outdoors | Apr 29 – May 22 |
| Peas | Sow outdoors (spring) | Mar 6 – Apr 21 |
| Potatoes | Plant outdoors (spring) | Mar 6 – May 6 |
| Onions | Start seeds indoors (spring) | Jan 23 – Feb 19 |
| Onions | Transplant outdoors (spring) | Mar 23 – Apr 21 |
| Broccoli | Start seeds indoors (spring) | Feb 16 – Mar 22 |
| Broccoli | Transplant outdoors (spring) | Mar 23 – Apr 21 |
| Broccoli | Start seeds indoors (fall) | Jun 24 – Jul 4 |
| Broccoli | Transplant outdoors (fall) | Jul 24 – Aug 4 |
| Cabbage | Start seeds indoors (spring) | Feb 6 – Mar 6 |
| Cabbage | Transplant outdoors (spring) | Mar 6 – Apr 6 |
| Cabbage | Start seeds indoors (fall) | Jun 14 – Jul 14 |
| Cabbage | Transplant outdoors (fall) | Jul 14 – Aug 14 |
| Leaf lettuce | Sow outdoors (spring) | Mar 6 – May 22 |
| Leaf lettuce | Sow outdoors (fall) | Jul 14 – Aug 30 |
| Spinach | Sow outdoors (spring) | Feb 27 – Apr 12 |
| Spinach | Sow outdoors (fall) | Jul 31 – Sep 4 |
| Radishes | Sow outdoors (spring) | Mar 6 – Apr 26 |
| Radishes | Sow outdoors (fall) | Jul 14 – Sep 14 |
| Kale | Sow outdoors (spring) | Mar 23 – Apr 12 |
| Kale | Sow outdoors (fall) | Jul 7 – Aug 14 |
| Carrots | Sow outdoors (spring) | Apr 6 – May 22 |
| Carrots | Sow outdoors (fall) | Jun 14 – Jul 30 |
| Garlic | Plant outdoors (fall) | Oct 14 – Nov 14 |
Where these dates come from
ZIP code 99352 is matched to the NOAA station Richland, WA, 6.9 km away, at 373 ft elevation (34 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Richland, WA (used) | 373 ft | Apr 6 | Oct 24 |
| Pasco Tri Cities Ap, WA | 407 ft | Apr 27 | Oct 11 |
| Kennewick, WA | 390 ft | Mar 28 | Oct 30 |
| Eltopia 8 Wsw, WA | 700 ft | Apr 21 | Oct 22 |
Frost dates near Richland
- Richland, WA 99354 · last Apr 6, first Oct 24
- West Richland, WA 99353 · last Apr 6, first Oct 24
- Kennewick, WA 99336 · last Mar 28, first Oct 30
- Pasco, WA 99301 · last Apr 27, first Oct 11
- Benton City, WA 99320 · last Apr 6, first Oct 24
- Eltopia, WA 99330 · last Apr 21, first Oct 22
- Burbank, WA 99323 · last Apr 7, first Oct 22
- Wallula, WA 99363 · last Apr 7, first Oct 22
Frequently asked questions
- When is the last frost in Richland, WA?
- For ZIP code 99352, the average last spring frost (32°F) is April 6, based on NOAA 1991-2020 climate normals for the Richland, WA weather station. There is a 1-in-10 chance of a frost after April 24.
- When is the first frost in Richland, WA?
- The average first fall frost (32°F) is October 24. There is a 1-in-10 chance of frost by October 10, so tender plants are at risk from that point on.
- How long is the growing season in 99352?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 200 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.