Powell, WY frost dates
Last spring frostMay 19median date
First fall frostSep 20median date
Growing season124 daysfrost-free
Hardiness zone5aZone 5a
How Powell compares
- In 8 years out of 10, the last spring frost in Powell falls between May 5 and June 4, a 30-day window. The first fall frost falls between September 7 and October 1.
- The median last frost is 2 days earlier than the Wyoming median of May 21.
- Its 124-day growing season is longer than 46% of the 153 Wyoming places with a regular frost season (state median 125 days).
- The last frost is 16 days later than the zone 5a median of May 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5a chart.
- The weather station records an average of 191 nights a year at or below 32°F.
- Compared with Billings, MT, 118 km away, the last frost here is 15 days later than there and the growing season is 32 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 5 |
| 50% (median) | May 19 |
| 10% (safe for tender plants) | June 4 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 7 |
| 50% (median) | September 20 |
| 90% (late) | October 1 |
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 Powell, WY
Powell, WY frost dates — last frost May 19, first frost Sep 20, zone 5a. whenisthelastfrost.com
Crop
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Start indoors: Feb 24 to Mar 10Transplant outside: Apr 21 to May 5
Start indoors: Mar 10 to Mar 24Transplant outside: Jun 2 to Jun 16
Start indoors: Mar 10 to Mar 24Transplant outside: Jun 2 to Jun 16
Start indoors: Mar 24 to Apr 7Transplant outside: May 26 to Jun 9
Start indoors: Mar 24 to Apr 7Transplant outside: Apr 28 to May 12Sow outdoors: Apr 21 to May 26Plant for fall: Jul 26 to Aug 23
Start indoors: Mar 24 to Apr 7Transplant outside: Apr 21 to May 5Sow outdoors: Apr 21 to May 5Plant for fall: Jul 12 to Aug 2
Start indoors: Mar 24 to Apr 7Transplant outside: May 5 to May 19Plant for fall: Jun 14 to Jul 5
Start indoors: Mar 24 to Apr 7Transplant outside: Apr 28 to May 12Plant for fall: Jun 14 to Jul 5
Start indoors: Mar 24 to Apr 7Transplant outside: May 5 to May 19Plant for fall: Jun 14 to Jul 5
Start indoors: Apr 7 to Apr 21Transplant outside: Jun 9 to Jun 23Sow outdoors: Jun 9 to Jun 23
Start indoors: Apr 7 to Apr 21Transplant outside: May 26 to Jun 9
Sow outdoors: Apr 7 to Apr 28Plant for fall: Jun 28 to Jul 19
Sow outdoors: Apr 7 to Apr 28Plant for fall: Jul 26 to Aug 16
Sow outdoors: Apr 14 to May 26Plant for fall: Aug 9 to Aug 30
Start indoors: Apr 21 to Apr 28Transplant outside: Jun 2 to Jun 9Sow outdoors: May 26 to Jun 9Plant for fall: Jul 5 to Jul 19
Start indoors: Apr 21 to Apr 28Sow outdoors: May 26 to Jun 9Plant for fall: Jul 12 to Jul 26
Start indoors: Apr 21 to Apr 28Sow outdoors: May 26 to Jun 9
Start indoors: Apr 21 to Apr 28Transplant outside: Jun 2 to Jun 16
Sow outdoors: Apr 28 to May 26Plant for fall: Jun 28 to Jul 12
Sow outdoors: Apr 28 to May 26Plant for fall: Jul 12 to Jul 26
Sow outdoors: Apr 28 to May 19
Sow outdoors: May 5 to Jun 2Plant for fall: Jul 12 to Jul 26
Sow outdoors: May 5 to May 26Plant for fall: Jul 26 to Aug 16
Sow outdoors: May 26 to Jun 16Plant for fall: Jul 5 to Jul 19
Sow outdoors: May 26 to Jun 9
Transplant outside: Jun 2 to Jun 23
Plant for fall: Sep 6 to Oct 11
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Powell, WY
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 24 – Mar 10 | Apr 21 – May 5 | — | — |
| Peppers | Mar 10 – Mar 24 | Jun 2 – Jun 16 | — | — |
| Eggplant | Mar 10 – Mar 24 | Jun 2 – Jun 16 | — | — |
| Tomatoes | Mar 24 – Apr 7 | May 26 – Jun 9 | — | — |
| Lettuce | Mar 24 – Apr 7 | Apr 28 – May 12 | Apr 21 – May 26 | Jul 26 – Aug 23 |
| Kale | Mar 24 – Apr 7 | Apr 21 – May 5 | Apr 21 – May 5 | Jul 12 – Aug 2 |
| Broccoli | Mar 24 – Apr 7 | May 5 – May 19 | — | Jun 14 – Jul 5 |
| Cabbage | Mar 24 – Apr 7 | Apr 28 – May 12 | — | Jun 14 – Jul 5 |
| Cauliflower | Mar 24 – Apr 7 | May 5 – May 19 | — | Jun 14 – Jul 5 |
| Okra | Apr 7 – Apr 21 | Jun 9 – Jun 23 | Jun 9 – Jun 23 | — |
| Basil | Apr 7 – Apr 21 | May 26 – Jun 9 | — | — |
| Peas | — | — | Apr 7 – Apr 28 | Jun 28 – Jul 19 |
| Spinach | — | — | Apr 7 – Apr 28 | Jul 26 – Aug 16 |
| Radishes | — | — | Apr 14 – May 26 | Aug 9 – Aug 30 |
| Cucumbers | Apr 21 – Apr 28 | Jun 2 – Jun 9 | May 26 – Jun 9 | Jul 5 – Jul 19 |
| Zucchini & Summer Squash | Apr 21 – Apr 28 | — | May 26 – Jun 9 | Jul 12 – Jul 26 |
| Winter Squash & Pumpkins | Apr 21 – Apr 28 | — | May 26 – Jun 9 | — |
| Melons & Watermelon | Apr 21 – Apr 28 | Jun 2 – Jun 16 | — | — |
| Carrots | — | — | Apr 28 – May 26 | Jun 28 – Jul 12 |
| Beets | — | — | Apr 28 – May 26 | Jul 12 – Jul 26 |
| Potatoes | — | — | Apr 28 – May 19 | — |
| Swiss Chard | — | — | May 5 – Jun 2 | Jul 12 – Jul 26 |
| Cilantro | — | — | May 5 – May 26 | Jul 26 – Aug 16 |
| Green Beans | — | — | May 26 – Jun 16 | Jul 5 – Jul 19 |
| Sweet Corn | — | — | May 26 – Jun 9 | — |
| Sweet Potatoes | — | Jun 2 – Jun 23 | — | — |
| Garlic | — | — | — | Sep 6 – Oct 11 |
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 Powell Fld Stn, WY weather station, 3 km away (elevation 4,373 ft (1,333 m)).
Frost dates near Powell
- Ralston May 15 · Sep 25
- Byron May 9 · Sep 29
- Deaver May 6 · Oct 1
- Frannie May 6 · Oct 1
- Cowley May 9 · Sep 29
- Lovell May 9 · Sep 29
- Cody May 12 · Oct 1
- Emblem May 12 · Sep 28
- Burlington May 12 · Sep 28
- Otto May 12 · Sep 28
Frequently asked questions
When is the last frost in Powell, WY?
The median last spring frost in Powell, WY is May 19. There is still about a 10% chance of frost after June 4, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Powell, WY?
The median first fall frost is September 20, with about a 10% chance of frost before September 7.
How long is the growing season in Powell, WY?
About 124 days between the median last spring frost and first fall frost.
What planting zone is Powell, WY?
Powell, WY is in USDA hardiness zone 5a.