Hillsdale, WY frost dates
Last spring frostMay 21median date
First fall frostSep 24median date
Growing season126 daysfrost-free
Hardiness zone5aZone 5a
How Hillsdale compares
- In 8 years out of 10, the last spring frost in Hillsdale falls between May 8 and June 6, a 29-day window. The first fall frost falls between September 8 and October 5.
- The median last frost is the same as the Wyoming median of May 21.
- Its 126-day growing season is longer than 50% of the 153 Wyoming places with a regular frost season (state median 125 days).
- The last frost is 18 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 196 nights a year at or below 32°F.
- Compared with Cheyenne, WY, 26 km away, the last frost here is 9 days later than there and the growing season is 16 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 8 |
| 50% (median) | May 21 |
| 10% (safe for tender plants) | June 6 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 8 |
| 50% (median) | September 24 |
| 90% (late) | October 5 |
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 Hillsdale, WY
Hillsdale, WY frost dates — last frost May 21, first frost Sep 24, zone 5a. whenisthelastfrost.com
Crop
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Start indoors: Feb 26 to Mar 12Transplant outside: Apr 23 to May 7
Start indoors: Mar 12 to Mar 26Transplant outside: Jun 4 to Jun 18
Start indoors: Mar 12 to Mar 26Transplant outside: Jun 4 to Jun 18
Start indoors: Mar 26 to Apr 9Transplant outside: May 28 to Jun 11
Start indoors: Mar 26 to Apr 9Transplant outside: Apr 30 to May 14Sow outdoors: Apr 23 to May 28Plant for fall: Jul 30 to Aug 27
Start indoors: Mar 26 to Apr 9Transplant outside: Apr 23 to May 7Sow outdoors: Apr 23 to May 7Plant for fall: Jul 16 to Aug 6
Start indoors: Mar 26 to Apr 9Transplant outside: May 7 to May 21Plant for fall: Jun 18 to Jul 9
Start indoors: Mar 26 to Apr 9Transplant outside: Apr 30 to May 14Plant for fall: Jun 18 to Jul 9
Start indoors: Mar 26 to Apr 9Transplant outside: May 7 to May 21Plant for fall: Jun 18 to Jul 9
Start indoors: Apr 9 to Apr 23Transplant outside: Jun 11 to Jun 25Sow outdoors: Jun 11 to Jun 25
Start indoors: Apr 9 to Apr 23Transplant outside: May 28 to Jun 11
Sow outdoors: Apr 9 to Apr 30Plant for fall: Jul 2 to Jul 23
Sow outdoors: Apr 9 to Apr 30Plant for fall: Jul 30 to Aug 20
Sow outdoors: Apr 16 to May 28Plant for fall: Aug 13 to Sep 3
Start indoors: Apr 23 to Apr 30Transplant outside: Jun 4 to Jun 11Sow outdoors: May 28 to Jun 11Plant for fall: Jul 9 to Jul 23
Start indoors: Apr 23 to Apr 30Sow outdoors: May 28 to Jun 11Plant for fall: Jul 16 to Jul 30
Start indoors: Apr 23 to Apr 30Sow outdoors: May 28 to Jun 11
Start indoors: Apr 23 to Apr 30Transplant outside: Jun 4 to Jun 18
Sow outdoors: Apr 30 to May 28Plant for fall: Jul 2 to Jul 16
Sow outdoors: Apr 30 to May 28Plant for fall: Jul 16 to Jul 30
Sow outdoors: Apr 30 to May 21
Sow outdoors: May 7 to Jun 4Plant for fall: Jul 16 to Jul 30
Sow outdoors: May 7 to May 28Plant for fall: Jul 30 to Aug 20
Sow outdoors: May 28 to Jun 18Plant for fall: Jul 9 to Jul 23
Sow outdoors: May 28 to Jun 11
Transplant outside: Jun 4 to Jun 25
Plant for fall: Sep 10 to Oct 15
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Hillsdale, WY
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 26 – Mar 12 | Apr 23 – May 7 | — | — |
| Peppers | Mar 12 – Mar 26 | Jun 4 – Jun 18 | — | — |
| Eggplant | Mar 12 – Mar 26 | Jun 4 – Jun 18 | — | — |
| Tomatoes | Mar 26 – Apr 9 | May 28 – Jun 11 | — | — |
| Lettuce | Mar 26 – Apr 9 | Apr 30 – May 14 | Apr 23 – May 28 | Jul 30 – Aug 27 |
| Kale | Mar 26 – Apr 9 | Apr 23 – May 7 | Apr 23 – May 7 | Jul 16 – Aug 6 |
| Broccoli | Mar 26 – Apr 9 | May 7 – May 21 | — | Jun 18 – Jul 9 |
| Cabbage | Mar 26 – Apr 9 | Apr 30 – May 14 | — | Jun 18 – Jul 9 |
| Cauliflower | Mar 26 – Apr 9 | May 7 – May 21 | — | Jun 18 – Jul 9 |
| Okra | Apr 9 – Apr 23 | Jun 11 – Jun 25 | Jun 11 – Jun 25 | — |
| Basil | Apr 9 – Apr 23 | May 28 – Jun 11 | — | — |
| Peas | — | — | Apr 9 – Apr 30 | Jul 2 – Jul 23 |
| Spinach | — | — | Apr 9 – Apr 30 | Jul 30 – Aug 20 |
| Radishes | — | — | Apr 16 – May 28 | Aug 13 – Sep 3 |
| Cucumbers | Apr 23 – Apr 30 | Jun 4 – Jun 11 | May 28 – Jun 11 | Jul 9 – Jul 23 |
| Zucchini & Summer Squash | Apr 23 – Apr 30 | — | May 28 – Jun 11 | Jul 16 – Jul 30 |
| Winter Squash & Pumpkins | Apr 23 – Apr 30 | — | May 28 – Jun 11 | — |
| Melons & Watermelon | Apr 23 – Apr 30 | Jun 4 – Jun 18 | — | — |
| Carrots | — | — | Apr 30 – May 28 | Jul 2 – Jul 16 |
| Beets | — | — | Apr 30 – May 28 | Jul 16 – Jul 30 |
| Potatoes | — | — | Apr 30 – May 21 | — |
| Swiss Chard | — | — | May 7 – Jun 4 | Jul 16 – Jul 30 |
| Cilantro | — | — | May 7 – May 28 | Jul 30 – Aug 20 |
| Green Beans | — | — | May 28 – Jun 18 | Jul 9 – Jul 23 |
| Sweet Corn | — | — | May 28 – Jun 11 | — |
| Sweet Potatoes | — | Jun 4 – Jun 25 | — | — |
| Garlic | — | — | — | Sep 10 – Oct 15 |
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 Archer, WY weather station, 15 km away (elevation 6,010 ft (1,832 m)).
Frost dates near Hillsdale
- Burns May 16 · Sep 27
- Cheyenne May 12 · Oct 1
- Carpenter May 14 · Sep 26
- Fe Warren Afb May 14 · Oct 1
- Pine Bluffs May 10 · Oct 1
- Albin May 14 · Oct 2
- Meriden May 14 · Oct 1
- Lagrange May 14 · Oct 1
- Granite Canon May 31 · Sep 19
- Horse Creek May 27 · Sep 19
Frequently asked questions
When is the last frost in Hillsdale, WY?
The median last spring frost in Hillsdale, WY is May 21. There is still about a 10% chance of frost after June 6, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Hillsdale, WY?
The median first fall frost is September 24, with about a 10% chance of frost before September 8.
How long is the growing season in Hillsdale, WY?
About 126 days between the median last spring frost and first fall frost.
What planting zone is Hillsdale, WY?
Hillsdale, WY is in USDA hardiness zone 5a.