Ritzville, WA frost dates
Last spring frostMay 7median date
First fall frostOct 10median date
Growing season156 daysfrost-free
Hardiness zone6bZone 6b
How Ritzville compares
- In 8 years out of 10, the last spring frost in Ritzville falls between April 25 and May 27, a 32-day window. The first fall frost falls between September 27 and October 25.
- The median last frost is 16 days later than the Washington median of Apr 21.
- Its 156-day growing season is longer than 23% of the 491 Washington places with a regular frost season (state median 182 days).
- The last frost is 15 days later than the zone 6b median of Apr 22. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6b chart.
- The weather station records an average of 148 nights a year at or below 32°F.
- Compared with Spokane, WA, 96 km away, the last frost here is 11 days later than there and the growing season is 16 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 25 |
| 50% (median) | May 7 |
| 10% (safe for tender plants) | May 27 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 27 |
| 50% (median) | October 10 |
| 90% (late) | October 25 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Ritzville, WA
Ritzville, WA frost dates — last frost May 7, first frost Oct 10, zone 6b. whenisthelastfrost.com
Crop
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Start indoors: Feb 12 to Feb 26Transplant outside: Apr 9 to Apr 23
Start indoors: Feb 26 to Mar 12Transplant outside: May 21 to Jun 4
Start indoors: Feb 26 to Mar 12Transplant outside: May 21 to Jun 4
Start indoors: Mar 12 to Mar 26Transplant outside: May 14 to May 28
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 16 to Apr 30Sow outdoors: Apr 9 to May 14Plant for fall: Aug 15 to Sep 12
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 9 to Apr 23Sow outdoors: Apr 9 to Apr 23Plant for fall: Aug 1 to Aug 22
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 23 to May 7Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 16 to Apr 30Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 23 to May 7Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 26 to Apr 9Transplant outside: May 28 to Jun 11Sow outdoors: May 28 to Jun 11
Start indoors: Mar 26 to Apr 9Transplant outside: May 14 to May 28
Sow outdoors: Mar 26 to Apr 16Plant for fall: Jul 18 to Aug 8
Sow outdoors: Mar 26 to Apr 16Plant for fall: Aug 15 to Sep 5
Sow outdoors: Apr 2 to May 14Plant for fall: Aug 29 to Sep 19
Start indoors: Apr 9 to Apr 16Transplant outside: May 21 to May 28Sow outdoors: May 14 to May 28Plant for fall: Jul 25 to Aug 8
Start indoors: Apr 9 to Apr 16Sow outdoors: May 14 to May 28Plant for fall: Aug 1 to Aug 15
Start indoors: Apr 9 to Apr 16Sow outdoors: May 14 to May 28
Start indoors: Apr 9 to Apr 16Transplant outside: May 21 to Jun 4
Sow outdoors: Apr 16 to May 14Plant for fall: Jul 18 to Aug 1
Sow outdoors: Apr 16 to May 14Plant for fall: Aug 1 to Aug 15
Sow outdoors: Apr 16 to May 7
Sow outdoors: Apr 23 to May 21Plant for fall: Aug 1 to Aug 15
Sow outdoors: Apr 23 to May 14Plant for fall: Aug 15 to Sep 5
Sow outdoors: May 14 to Jun 4Plant for fall: Jul 25 to Aug 8
Sow outdoors: May 14 to May 28
Transplant outside: May 21 to Jun 11
Plant for fall: Sep 26 to Oct 31
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Ritzville, WA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 12 – Feb 26 | Apr 9 – Apr 23 | — | — |
| Peppers | Feb 26 – Mar 12 | May 21 – Jun 4 | — | — |
| Eggplant | Feb 26 – Mar 12 | May 21 – Jun 4 | — | — |
| Tomatoes | Mar 12 – Mar 26 | May 14 – May 28 | — | — |
| Lettuce | Mar 12 – Mar 26 | Apr 16 – Apr 30 | Apr 9 – May 14 | Aug 15 – Sep 12 |
| Kale | Mar 12 – Mar 26 | Apr 9 – Apr 23 | Apr 9 – Apr 23 | Aug 1 – Aug 22 |
| Broccoli | Mar 12 – Mar 26 | Apr 23 – May 7 | — | Jul 4 – Jul 25 |
| Cabbage | Mar 12 – Mar 26 | Apr 16 – Apr 30 | — | Jul 4 – Jul 25 |
| Cauliflower | Mar 12 – Mar 26 | Apr 23 – May 7 | — | Jul 4 – Jul 25 |
| Okra | Mar 26 – Apr 9 | May 28 – Jun 11 | May 28 – Jun 11 | — |
| Basil | Mar 26 – Apr 9 | May 14 – May 28 | — | — |
| Peas | — | — | Mar 26 – Apr 16 | Jul 18 – Aug 8 |
| Spinach | — | — | Mar 26 – Apr 16 | Aug 15 – Sep 5 |
| Radishes | — | — | Apr 2 – May 14 | Aug 29 – Sep 19 |
| Cucumbers | Apr 9 – Apr 16 | May 21 – May 28 | May 14 – May 28 | Jul 25 – Aug 8 |
| Zucchini & Summer Squash | Apr 9 – Apr 16 | — | May 14 – May 28 | Aug 1 – Aug 15 |
| Winter Squash & Pumpkins | Apr 9 – Apr 16 | — | May 14 – May 28 | — |
| Melons & Watermelon | Apr 9 – Apr 16 | May 21 – Jun 4 | — | — |
| Carrots | — | — | Apr 16 – May 14 | Jul 18 – Aug 1 |
| Beets | — | — | Apr 16 – May 14 | Aug 1 – Aug 15 |
| Potatoes | — | — | Apr 16 – May 7 | — |
| Swiss Chard | — | — | Apr 23 – May 21 | Aug 1 – Aug 15 |
| Cilantro | — | — | Apr 23 – May 14 | Aug 15 – Sep 5 |
| Green Beans | — | — | May 14 – Jun 4 | Jul 25 – Aug 8 |
| Sweet Corn | — | — | May 14 – May 28 | — |
| Sweet Potatoes | — | May 21 – Jun 11 | — | — |
| Garlic | — | — | — | Sep 26 – Oct 31 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Ritzville 1 Sse, WA weather station, 2 km away (elevation 1,864 ft (568 m)).
Frost dates near Ritzville
- Lamona May 14 · Sep 26
- Mohler May 31 · Sep 12
- Lind May 7 · Oct 4
- Odessa May 14 · Sep 26
- Benge May 13 · Sep 26
- Washtucna May 7 · Oct 4
- Harrington May 31 · Sep 12
- Sprague May 31 · Sep 12
- Lamont Apr 29 · Oct 4
- Hooper May 13 · Sep 26
Frequently asked questions
When is the last frost in Ritzville, WA?
The median last spring frost in Ritzville, WA is May 7. There is still about a 10% chance of frost after May 27, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Ritzville, WA?
The median first fall frost is October 10, with about a 10% chance of frost before September 27.
How long is the growing season in Ritzville, WA?
About 156 days between the median last spring frost and first fall frost.
What planting zone is Ritzville, WA?
Ritzville, WA is in USDA hardiness zone 6b.