Mazama, WA frost dates
Last spring frostMay 9median date
First fall frostSep 29median date
Growing season143 daysfrost-free
Hardiness zone6aZone 6a
How Mazama compares
- In 8 years out of 10, the last spring frost in Mazama falls between April 28 and May 24, a 26-day window. The first fall frost falls between September 15 and October 10.
- The median last frost is 18 days later than the Washington median of Apr 21.
- Its 143-day growing season is longer than 12% of the 491 Washington places with a regular frost season (state median 182 days).
- The last frost is 10 days later than the zone 6a median of Apr 29. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6a chart.
- The weather station records an average of 180 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 28 |
| 50% (median) | May 9 |
| 10% (safe for tender plants) | May 24 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 15 |
| 50% (median) | September 29 |
| 90% (late) | October 10 |
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 Mazama, WA
Mazama, WA frost dates — last frost May 9, first frost Sep 29, zone 6a. whenisthelastfrost.com
Crop
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Start indoors: Feb 14 to Feb 28Transplant outside: Apr 11 to Apr 25
Start indoors: Feb 28 to Mar 14Transplant outside: May 23 to Jun 6
Start indoors: Feb 28 to Mar 14Transplant outside: May 23 to Jun 6
Start indoors: Mar 14 to Mar 28Transplant outside: May 16 to May 30
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 18 to May 2Sow outdoors: Apr 11 to May 16Plant for fall: Aug 4 to Sep 1
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 11 to Apr 25Sow outdoors: Apr 11 to Apr 25Plant for fall: Jul 21 to Aug 11
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 25 to May 9Plant for fall: Jun 23 to Jul 14
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 18 to May 2Plant for fall: Jun 23 to Jul 14
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 25 to May 9Plant for fall: Jun 23 to Jul 14
Start indoors: Mar 28 to Apr 11Transplant outside: May 30 to Jun 13Sow outdoors: May 30 to Jun 13
Start indoors: Mar 28 to Apr 11Transplant outside: May 16 to May 30
Sow outdoors: Mar 28 to Apr 18Plant for fall: Jul 7 to Jul 28
Sow outdoors: Mar 28 to Apr 18Plant for fall: Aug 4 to Aug 25
Sow outdoors: Apr 4 to May 16Plant for fall: Aug 18 to Sep 8
Start indoors: Apr 11 to Apr 18Transplant outside: May 23 to May 30Sow outdoors: May 16 to May 30Plant for fall: Jul 14 to Jul 28
Start indoors: Apr 11 to Apr 18Sow outdoors: May 16 to May 30Plant for fall: Jul 21 to Aug 4
Start indoors: Apr 11 to Apr 18Sow outdoors: May 16 to May 30
Start indoors: Apr 11 to Apr 18Transplant outside: May 23 to Jun 6
Sow outdoors: Apr 18 to May 16Plant for fall: Jul 7 to Jul 21
Sow outdoors: Apr 18 to May 16Plant for fall: Jul 21 to Aug 4
Sow outdoors: Apr 18 to May 9
Sow outdoors: Apr 25 to May 23Plant for fall: Jul 21 to Aug 4
Sow outdoors: Apr 25 to May 16Plant for fall: Aug 4 to Aug 25
Sow outdoors: May 16 to Jun 6Plant for fall: Jul 14 to Jul 28
Sow outdoors: May 16 to May 30
Transplant outside: May 23 to Jun 13
Plant for fall: Sep 15 to Oct 20
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Mazama, WA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 14 – Feb 28 | Apr 11 – Apr 25 | — | — |
| Peppers | Feb 28 – Mar 14 | May 23 – Jun 6 | — | — |
| Eggplant | Feb 28 – Mar 14 | May 23 – Jun 6 | — | — |
| Tomatoes | Mar 14 – Mar 28 | May 16 – May 30 | — | — |
| Lettuce | Mar 14 – Mar 28 | Apr 18 – May 2 | Apr 11 – May 16 | Aug 4 – Sep 1 |
| Kale | Mar 14 – Mar 28 | Apr 11 – Apr 25 | Apr 11 – Apr 25 | Jul 21 – Aug 11 |
| Broccoli | Mar 14 – Mar 28 | Apr 25 – May 9 | — | Jun 23 – Jul 14 |
| Cabbage | Mar 14 – Mar 28 | Apr 18 – May 2 | — | Jun 23 – Jul 14 |
| Cauliflower | Mar 14 – Mar 28 | Apr 25 – May 9 | — | Jun 23 – Jul 14 |
| Okra | Mar 28 – Apr 11 | May 30 – Jun 13 | May 30 – Jun 13 | — |
| Basil | Mar 28 – Apr 11 | May 16 – May 30 | — | — |
| Peas | — | — | Mar 28 – Apr 18 | Jul 7 – Jul 28 |
| Spinach | — | — | Mar 28 – Apr 18 | Aug 4 – Aug 25 |
| Radishes | — | — | Apr 4 – May 16 | Aug 18 – Sep 8 |
| Cucumbers | Apr 11 – Apr 18 | May 23 – May 30 | May 16 – May 30 | Jul 14 – Jul 28 |
| Zucchini & Summer Squash | Apr 11 – Apr 18 | — | May 16 – May 30 | Jul 21 – Aug 4 |
| Winter Squash & Pumpkins | Apr 11 – Apr 18 | — | May 16 – May 30 | — |
| Melons & Watermelon | Apr 11 – Apr 18 | May 23 – Jun 6 | — | — |
| Carrots | — | — | Apr 18 – May 16 | Jul 7 – Jul 21 |
| Beets | — | — | Apr 18 – May 16 | Jul 21 – Aug 4 |
| Potatoes | — | — | Apr 18 – May 9 | — |
| Swiss Chard | — | — | Apr 25 – May 23 | Jul 21 – Aug 4 |
| Cilantro | — | — | Apr 25 – May 16 | Aug 4 – Aug 25 |
| Green Beans | — | — | May 16 – Jun 6 | Jul 14 – Jul 28 |
| Sweet Corn | — | — | May 16 – May 30 | — |
| Sweet Potatoes | — | May 23 – Jun 13 | — | — |
| Garlic | — | — | — | Sep 15 – Oct 20 |
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 Mazama, WA weather station, 3 km away (elevation 2,142 ft (653 m)).
Frost dates near Mazama
- Winthrop May 15 · Sep 22
- Twisp May 15 · Sep 22
- Stehekin Apr 27 · Oct 17
- Carlton Apr 21 · Oct 15
- Conconully Apr 30 · Oct 7
- Methow Apr 21 · Oct 15
- Riverside Apr 30 · Oct 7
- Malott Apr 21 · Oct 15
- Loomis Apr 26 · Oct 10
- Okanogan Apr 30 · Oct 7
Frequently asked questions
When is the last frost in Mazama, WA?
The median last spring frost in Mazama, WA is May 9. There is still about a 10% chance of frost after May 24, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Mazama, WA?
The median first fall frost is September 29, with about a 10% chance of frost before September 15.
How long is the growing season in Mazama, WA?
About 143 days between the median last spring frost and first fall frost.
What planting zone is Mazama, WA?
Mazama, WA is in USDA hardiness zone 6a.