Douglas, WY frost dates
Last spring frostMay 19median date
First fall frostSep 23median date
Growing season127 daysfrost-free
Hardiness zone5aZone 5a
How Douglas compares
- In 8 years out of 10, the last spring frost in Douglas falls between May 7 and June 2, a 26-day window. The first fall frost falls between September 10 and October 6.
- The median last frost is 2 days earlier than the Wyoming median of May 21.
- Its 127-day growing season is longer than 53% 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 182 nights a year at or below 32°F.
- Compared with Casper, WY, 78 km away, the last frost here is 9 days later than there and the growing season is 15 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 7 |
| 50% (median) | May 19 |
| 10% (safe for tender plants) | June 2 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 10 |
| 50% (median) | September 23 |
| 90% (late) | October 6 |
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 Douglas, WY
Douglas, WY frost dates — last frost May 19, first frost Sep 23, zone 5a. whenisthelastfrost.com
Crop
JFMAMJJASOND
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 29 to Aug 26
Start indoors: Mar 24 to Apr 7Transplant outside: Apr 21 to May 5Sow outdoors: Apr 21 to May 5Plant for fall: Jul 15 to Aug 5
Start indoors: Mar 24 to Apr 7Transplant outside: May 5 to May 19Plant for fall: Jun 17 to Jul 8
Start indoors: Mar 24 to Apr 7Transplant outside: Apr 28 to May 12Plant for fall: Jun 17 to Jul 8
Start indoors: Mar 24 to Apr 7Transplant outside: May 5 to May 19Plant for fall: Jun 17 to Jul 8
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: Jul 1 to Jul 22
Sow outdoors: Apr 7 to Apr 28Plant for fall: Jul 29 to Aug 19
Sow outdoors: Apr 14 to May 26Plant for fall: Aug 12 to Sep 2
Start indoors: Apr 21 to Apr 28Transplant outside: Jun 2 to Jun 9Sow outdoors: May 26 to Jun 9Plant for fall: Jul 8 to Jul 22
Start indoors: Apr 21 to Apr 28Sow outdoors: May 26 to Jun 9Plant for fall: Jul 15 to Jul 29
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: Jul 1 to Jul 15
Sow outdoors: Apr 28 to May 26Plant for fall: Jul 15 to Jul 29
Sow outdoors: Apr 28 to May 19
Sow outdoors: May 5 to Jun 2Plant for fall: Jul 15 to Jul 29
Sow outdoors: May 5 to May 26Plant for fall: Jul 29 to Aug 19
Sow outdoors: May 26 to Jun 16Plant for fall: Jul 8 to Jul 22
Sow outdoors: May 26 to Jun 9
Transplant outside: Jun 2 to Jun 23
Plant for fall: Sep 9 to Oct 14
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Douglas, 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 29 – Aug 26 |
| Kale | Mar 24 – Apr 7 | Apr 21 – May 5 | Apr 21 – May 5 | Jul 15 – Aug 5 |
| Broccoli | Mar 24 – Apr 7 | May 5 – May 19 | — | Jun 17 – Jul 8 |
| Cabbage | Mar 24 – Apr 7 | Apr 28 – May 12 | — | Jun 17 – Jul 8 |
| Cauliflower | Mar 24 – Apr 7 | May 5 – May 19 | — | Jun 17 – Jul 8 |
| 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 | Jul 1 – Jul 22 |
| Spinach | — | — | Apr 7 – Apr 28 | Jul 29 – Aug 19 |
| Radishes | — | — | Apr 14 – May 26 | Aug 12 – Sep 2 |
| Cucumbers | Apr 21 – Apr 28 | Jun 2 – Jun 9 | May 26 – Jun 9 | Jul 8 – Jul 22 |
| Zucchini & Summer Squash | Apr 21 – Apr 28 | — | May 26 – Jun 9 | Jul 15 – Jul 29 |
| 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 | Jul 1 – Jul 15 |
| Beets | — | — | Apr 28 – May 26 | Jul 15 – Jul 29 |
| Potatoes | — | — | Apr 28 – May 19 | — |
| Swiss Chard | — | — | May 5 – Jun 2 | Jul 15 – Jul 29 |
| Cilantro | — | — | May 5 – May 26 | Jul 29 – Aug 19 |
| Green Beans | — | — | May 26 – Jun 16 | Jul 8 – Jul 22 |
| Sweet Corn | — | — | May 26 – Jun 9 | — |
| Sweet Potatoes | — | Jun 2 – Jun 23 | — | — |
| Garlic | — | — | — | Sep 9 – Oct 14 |
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 Douglas 1 Se, WY weather station, 3 km away (elevation 4,869 ft (1,484 m)).
Frost dates near Douglas
- Shawnee May 25 · Sep 15
- Glenrock May 12 · Oct 1
- Glendo May 9 · Oct 5
- Manville May 23 · Sep 20
- Lost Springs May 17 · Sep 25
- Evansville May 12 · Oct 1
- Garrett Jun 2 · Sep 9
- Lance Creek May 17 · Sep 25
- Hartville May 11 · Oct 3
- Lusk May 23 · Sep 20
Frequently asked questions
When is the last frost in Douglas, WY?
The median last spring frost in Douglas, WY is May 19. There is still about a 10% chance of frost after June 2, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Douglas, WY?
The median first fall frost is September 23, with about a 10% chance of frost before September 10.
How long is the growing season in Douglas, WY?
About 127 days between the median last spring frost and first fall frost.
What planting zone is Douglas, WY?
Douglas, WY is in USDA hardiness zone 5a.