Frost dates for 82901 — Rock Springs, WY
Last spring frostMay 24median date
First fall frostSep 24median date
Growing season123 daysfrost-free
Hardiness zone5bZone 5b
How Rock Springs compares
- In 8 years out of 10, the last spring frost in Rock Springs falls between May 8 and June 9, a 32-day window. The first fall frost falls between September 9 and October 4.
- The median last frost is 3 days later than the Wyoming median of May 21.
- Its 123-day growing season is longer than 43% of the 153 Wyoming places with a regular frost season (state median 125 days).
- The last frost is 23 days later than the zone 5b median of May 1. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5b chart.
- The weather station records an average of 184 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 8 |
| 50% (median) | May 24 |
| 10% (safe for tender plants) | June 9 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 9 |
| 50% (median) | September 24 |
| 90% (late) | October 4 |
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 Rock Springs, WY
Frost dates for 82901 — Rock Springs, WY — last frost May 24, first frost Sep 24, zone 5b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Mar 1 to Mar 15Transplant outside: Apr 26 to May 10
Start indoors: Mar 15 to Mar 29Transplant outside: Jun 7 to Jun 21
Start indoors: Mar 15 to Mar 29Transplant outside: Jun 7 to Jun 21
Start indoors: Mar 29 to Apr 12Transplant outside: May 31 to Jun 14
Start indoors: Mar 29 to Apr 12Transplant outside: May 3 to May 17Sow outdoors: Apr 26 to May 31Plant for fall: Jul 30 to Aug 27
Start indoors: Mar 29 to Apr 12Transplant outside: Apr 26 to May 10Sow outdoors: Apr 26 to May 10Plant for fall: Jul 16 to Aug 6
Start indoors: Mar 29 to Apr 12Transplant outside: May 10 to May 24Plant for fall: Jun 18 to Jul 9
Start indoors: Mar 29 to Apr 12Transplant outside: May 3 to May 17Plant for fall: Jun 18 to Jul 9
Start indoors: Mar 29 to Apr 12Transplant outside: May 10 to May 24Plant for fall: Jun 18 to Jul 9
Start indoors: Apr 12 to Apr 26Transplant outside: Jun 14 to Jun 28Sow outdoors: Jun 14 to Jun 28
Start indoors: Apr 12 to Apr 26Transplant outside: May 31 to Jun 14
Sow outdoors: Apr 12 to May 3Plant for fall: Jul 2 to Jul 23
Sow outdoors: Apr 12 to May 3Plant for fall: Jul 30 to Aug 20
Sow outdoors: Apr 19 to May 31Plant for fall: Aug 13 to Sep 3
Start indoors: Apr 26 to May 3Transplant outside: Jun 7 to Jun 14Sow outdoors: May 31 to Jun 14Plant for fall: Jul 9 to Jul 23
Start indoors: Apr 26 to May 3Sow outdoors: May 31 to Jun 14Plant for fall: Jul 16 to Jul 30
Start indoors: Apr 26 to May 3Sow outdoors: May 31 to Jun 14
Start indoors: Apr 26 to May 3Transplant outside: Jun 7 to Jun 21
Sow outdoors: May 3 to May 31Plant for fall: Jul 2 to Jul 16
Sow outdoors: May 3 to May 31Plant for fall: Jul 16 to Jul 30
Sow outdoors: May 3 to May 24
Sow outdoors: May 10 to Jun 7Plant for fall: Jul 16 to Jul 30
Sow outdoors: May 10 to May 31Plant for fall: Jul 30 to Aug 20
Sow outdoors: May 31 to Jun 21Plant for fall: Jul 9 to Jul 23
Sow outdoors: May 31 to Jun 14
Transplant outside: Jun 7 to Jun 28
Plant for fall: Sep 10 to Oct 15
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Rock Springs, WY
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 1 – Mar 15 | Apr 26 – May 10 | — | — |
| Peppers | Mar 15 – Mar 29 | Jun 7 – Jun 21 | — | — |
| Eggplant | Mar 15 – Mar 29 | Jun 7 – Jun 21 | — | — |
| Tomatoes | Mar 29 – Apr 12 | May 31 – Jun 14 | — | — |
| Lettuce | Mar 29 – Apr 12 | May 3 – May 17 | Apr 26 – May 31 | Jul 30 – Aug 27 |
| Kale | Mar 29 – Apr 12 | Apr 26 – May 10 | Apr 26 – May 10 | Jul 16 – Aug 6 |
| Broccoli | Mar 29 – Apr 12 | May 10 – May 24 | — | Jun 18 – Jul 9 |
| Cabbage | Mar 29 – Apr 12 | May 3 – May 17 | — | Jun 18 – Jul 9 |
| Cauliflower | Mar 29 – Apr 12 | May 10 – May 24 | — | Jun 18 – Jul 9 |
| Okra | Apr 12 – Apr 26 | Jun 14 – Jun 28 | Jun 14 – Jun 28 | — |
| Basil | Apr 12 – Apr 26 | May 31 – Jun 14 | — | — |
| Peas | — | — | Apr 12 – May 3 | Jul 2 – Jul 23 |
| Spinach | — | — | Apr 12 – May 3 | Jul 30 – Aug 20 |
| Radishes | — | — | Apr 19 – May 31 | Aug 13 – Sep 3 |
| Cucumbers | Apr 26 – May 3 | Jun 7 – Jun 14 | May 31 – Jun 14 | Jul 9 – Jul 23 |
| Zucchini & Summer Squash | Apr 26 – May 3 | — | May 31 – Jun 14 | Jul 16 – Jul 30 |
| Winter Squash & Pumpkins | Apr 26 – May 3 | — | May 31 – Jun 14 | — |
| Melons & Watermelon | Apr 26 – May 3 | Jun 7 – Jun 21 | — | — |
| Carrots | — | — | May 3 – May 31 | Jul 2 – Jul 16 |
| Beets | — | — | May 3 – May 31 | Jul 16 – Jul 30 |
| Potatoes | — | — | May 3 – May 24 | — |
| Swiss Chard | — | — | May 10 – Jun 7 | Jul 16 – Jul 30 |
| Cilantro | — | — | May 10 – May 31 | Jul 30 – Aug 20 |
| Green Beans | — | — | May 31 – Jun 21 | Jul 9 – Jul 23 |
| Sweet Corn | — | — | May 31 – Jun 14 | — |
| Sweet Potatoes | — | Jun 7 – Jun 28 | — | — |
| 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 Rock Springs Fire Dept, WY weather station, 3 km away (elevation 6,270 ft (1,911 m)).
ZIP codes in Rock Springs: 82901 82902
Frost dates near Rock Springs
- Reliance May 24 · Sep 24
- Green River May 24 · Sep 22
- Superior May 22 · Sep 28
- Point Of Rocks May 22 · Sep 28
- Little America May 25 · Sep 27
- Farson frost any month
- Granger May 25 · Sep 27
- Mc Kinnon May 22 · Sep 29
Frequently asked questions
When is the last frost in Rock Springs, WY?
The median last spring frost in Rock Springs, WY is May 24. There is still about a 10% chance of frost after June 9, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Rock Springs, WY?
The median first fall frost is September 24, with about a 10% chance of frost before September 9.
How long is the growing season in Rock Springs, WY?
About 123 days between the median last spring frost and first fall frost.
What planting zone is Rock Springs, WY?
Rock Springs, WY is in USDA hardiness zone 5b.