Hartville, WY frost dates
Last spring frostMay 11median date
First fall frostOct 3median date
Growing season145 daysfrost-free
Hardiness zone5aZone 5a
How Hartville compares
- In 8 years out of 10, the last spring frost in Hartville falls between April 29 and May 25, a 26-day window. The first fall frost falls between September 19 and October 15.
- The median last frost is 10 days earlier than the Wyoming median of May 21.
- Its 145-day growing season is longer than 93% of the 153 Wyoming places with a regular frost season (state median 125 days).
- The last frost is 8 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 174 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 29 |
| 50% (median) | May 11 |
| 10% (safe for tender plants) | May 25 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 19 |
| 50% (median) | October 3 |
| 90% (late) | October 15 |
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 Hartville, WY
Hartville, WY frost dates — last frost May 11, first frost Oct 3, zone 5a. whenisthelastfrost.com
Crop
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Start indoors: Feb 16 to Mar 2Transplant outside: Apr 13 to Apr 27
Start indoors: Mar 2 to Mar 16Transplant outside: May 25 to Jun 8
Start indoors: Mar 2 to Mar 16Transplant outside: May 25 to Jun 8
Start indoors: Mar 16 to Mar 30Transplant outside: May 18 to Jun 1
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 20 to May 4Sow outdoors: Apr 13 to May 18Plant for fall: Aug 8 to Sep 5
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 13 to Apr 27Sow outdoors: Apr 13 to Apr 27Plant for fall: Jul 25 to Aug 15
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 27 to May 11Plant for fall: Jun 27 to Jul 18
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 20 to May 4Plant for fall: Jun 27 to Jul 18
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 27 to May 11Plant for fall: Jun 27 to Jul 18
Start indoors: Mar 30 to Apr 13Transplant outside: Jun 1 to Jun 15Sow outdoors: Jun 1 to Jun 15
Start indoors: Mar 30 to Apr 13Transplant outside: May 18 to Jun 1
Sow outdoors: Mar 30 to Apr 20Plant for fall: Jul 11 to Aug 1
Sow outdoors: Mar 30 to Apr 20Plant for fall: Aug 8 to Aug 29
Sow outdoors: Apr 6 to May 18Plant for fall: Aug 22 to Sep 12
Start indoors: Apr 13 to Apr 20Transplant outside: May 25 to Jun 1Sow outdoors: May 18 to Jun 1Plant for fall: Jul 18 to Aug 1
Start indoors: Apr 13 to Apr 20Sow outdoors: May 18 to Jun 1Plant for fall: Jul 25 to Aug 8
Start indoors: Apr 13 to Apr 20Sow outdoors: May 18 to Jun 1
Start indoors: Apr 13 to Apr 20Transplant outside: May 25 to Jun 8
Sow outdoors: Apr 20 to May 18Plant for fall: Jul 11 to Jul 25
Sow outdoors: Apr 20 to May 18Plant for fall: Jul 25 to Aug 8
Sow outdoors: Apr 20 to May 11
Sow outdoors: Apr 27 to May 25Plant for fall: Jul 25 to Aug 8
Sow outdoors: Apr 27 to May 18Plant for fall: Aug 8 to Aug 29
Sow outdoors: May 18 to Jun 8Plant for fall: Jul 18 to Aug 1
Sow outdoors: May 18 to Jun 1
Transplant outside: May 25 to Jun 15
Plant for fall: Sep 19 to Oct 24
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Hartville, WY
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 16 – Mar 2 | Apr 13 – Apr 27 | — | — |
| Peppers | Mar 2 – Mar 16 | May 25 – Jun 8 | — | — |
| Eggplant | Mar 2 – Mar 16 | May 25 – Jun 8 | — | — |
| Tomatoes | Mar 16 – Mar 30 | May 18 – Jun 1 | — | — |
| Lettuce | Mar 16 – Mar 30 | Apr 20 – May 4 | Apr 13 – May 18 | Aug 8 – Sep 5 |
| Kale | Mar 16 – Mar 30 | Apr 13 – Apr 27 | Apr 13 – Apr 27 | Jul 25 – Aug 15 |
| Broccoli | Mar 16 – Mar 30 | Apr 27 – May 11 | — | Jun 27 – Jul 18 |
| Cabbage | Mar 16 – Mar 30 | Apr 20 – May 4 | — | Jun 27 – Jul 18 |
| Cauliflower | Mar 16 – Mar 30 | Apr 27 – May 11 | — | Jun 27 – Jul 18 |
| Okra | Mar 30 – Apr 13 | Jun 1 – Jun 15 | Jun 1 – Jun 15 | — |
| Basil | Mar 30 – Apr 13 | May 18 – Jun 1 | — | — |
| Peas | — | — | Mar 30 – Apr 20 | Jul 11 – Aug 1 |
| Spinach | — | — | Mar 30 – Apr 20 | Aug 8 – Aug 29 |
| Radishes | — | — | Apr 6 – May 18 | Aug 22 – Sep 12 |
| Cucumbers | Apr 13 – Apr 20 | May 25 – Jun 1 | May 18 – Jun 1 | Jul 18 – Aug 1 |
| Zucchini & Summer Squash | Apr 13 – Apr 20 | — | May 18 – Jun 1 | Jul 25 – Aug 8 |
| Winter Squash & Pumpkins | Apr 13 – Apr 20 | — | May 18 – Jun 1 | — |
| Melons & Watermelon | Apr 13 – Apr 20 | May 25 – Jun 8 | — | — |
| Carrots | — | — | Apr 20 – May 18 | Jul 11 – Jul 25 |
| Beets | — | — | Apr 20 – May 18 | Jul 25 – Aug 8 |
| Potatoes | — | — | Apr 20 – May 11 | — |
| Swiss Chard | — | — | Apr 27 – May 25 | Jul 25 – Aug 8 |
| Cilantro | — | — | Apr 27 – May 18 | Aug 8 – Aug 29 |
| Green Beans | — | — | May 18 – Jun 8 | Jul 18 – Aug 1 |
| Sweet Corn | — | — | May 18 – Jun 1 | — |
| Sweet Potatoes | — | May 25 – Jun 15 | — | — |
| Garlic | — | — | — | Sep 19 – Oct 24 |
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 Guernsey Dam #2, WY weather station, 5 km away (elevation 4,354 ft (1,327 m)).
Frost dates near Hartville
- Guernsey May 7 · Oct 6
- Fort Laramie May 14 · Sep 26
- Jay Em May 23 · Sep 20
- Glendo May 9 · Oct 5
- Wheatland May 19 · Sep 22
- Lingle May 20 · Sep 22
- Manville May 23 · Sep 20
- Veteran May 15 · Sep 27
- Shawnee May 25 · Sep 15
- Lusk May 23 · Sep 20
Frequently asked questions
When is the last frost in Hartville, WY?
The median last spring frost in Hartville, WY is May 11. There is still about a 10% chance of frost after May 25, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Hartville, WY?
The median first fall frost is October 3, with about a 10% chance of frost before September 19.
How long is the growing season in Hartville, WY?
About 145 days between the median last spring frost and first fall frost.
What planting zone is Hartville, WY?
Hartville, WY is in USDA hardiness zone 5a.