Guernsey, WY frost dates
Last spring frostMay 7median date
First fall frostOct 6median date
Growing season152 daysfrost-free
Hardiness zone5aZone 5a
How Guernsey compares
- In 8 years out of 10, the last spring frost in Guernsey falls between April 24 and May 21, a 27-day window. The first fall frost falls between September 23 and October 18.
- The median last frost is 14 days earlier than the Wyoming median of May 21.
- Its 152-day growing season is among the longest of the 153 Wyoming places with a regular frost season.
- The last frost is 4 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 161 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 24 |
| 50% (median) | May 7 |
| 10% (safe for tender plants) | May 21 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 23 |
| 50% (median) | October 6 |
| 90% (late) | October 18 |
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 Guernsey, WY
Guernsey, WY frost dates — last frost May 7, first frost Oct 6, zone 5a. whenisthelastfrost.com
Crop
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Start indoors: Feb 12 to Feb 26Transplant outside: Apr 9 to Apr 23
Start indoors: Feb 26 to Mar 12Transplant outside: May 21 to Jun 4
Start indoors: Feb 26 to Mar 12Transplant outside: May 21 to Jun 4
Start indoors: Mar 12 to Mar 26Transplant outside: May 14 to May 28
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 16 to Apr 30Sow outdoors: Apr 9 to May 14Plant for fall: Aug 11 to Sep 8
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 9 to Apr 23Sow outdoors: Apr 9 to Apr 23Plant for fall: Jul 28 to Aug 18
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 23 to May 7Plant for fall: Jun 30 to Jul 21
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 16 to Apr 30Plant for fall: Jun 30 to Jul 21
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 23 to May 7Plant for fall: Jun 30 to Jul 21
Start indoors: Mar 26 to Apr 9Transplant outside: May 28 to Jun 11Sow outdoors: May 28 to Jun 11
Start indoors: Mar 26 to Apr 9Transplant outside: May 14 to May 28
Sow outdoors: Mar 26 to Apr 16Plant for fall: Jul 14 to Aug 4
Sow outdoors: Mar 26 to Apr 16Plant for fall: Aug 11 to Sep 1
Sow outdoors: Apr 2 to May 14Plant for fall: Aug 25 to Sep 15
Start indoors: Apr 9 to Apr 16Transplant outside: May 21 to May 28Sow outdoors: May 14 to May 28Plant for fall: Jul 21 to Aug 4
Start indoors: Apr 9 to Apr 16Sow outdoors: May 14 to May 28Plant for fall: Jul 28 to Aug 11
Start indoors: Apr 9 to Apr 16Sow outdoors: May 14 to May 28
Start indoors: Apr 9 to Apr 16Transplant outside: May 21 to Jun 4
Sow outdoors: Apr 16 to May 14Plant for fall: Jul 14 to Jul 28
Sow outdoors: Apr 16 to May 14Plant for fall: Jul 28 to Aug 11
Sow outdoors: Apr 16 to May 7
Sow outdoors: Apr 23 to May 21Plant for fall: Jul 28 to Aug 11
Sow outdoors: Apr 23 to May 14Plant for fall: Aug 11 to Sep 1
Sow outdoors: May 14 to Jun 4Plant for fall: Jul 21 to Aug 4
Sow outdoors: May 14 to May 28
Transplant outside: May 21 to Jun 11
Plant for fall: Sep 22 to Oct 27
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Guernsey, WY
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 12 – Feb 26 | Apr 9 – Apr 23 | — | — |
| Peppers | Feb 26 – Mar 12 | May 21 – Jun 4 | — | — |
| Eggplant | Feb 26 – Mar 12 | May 21 – Jun 4 | — | — |
| Tomatoes | Mar 12 – Mar 26 | May 14 – May 28 | — | — |
| Lettuce | Mar 12 – Mar 26 | Apr 16 – Apr 30 | Apr 9 – May 14 | Aug 11 – Sep 8 |
| Kale | Mar 12 – Mar 26 | Apr 9 – Apr 23 | Apr 9 – Apr 23 | Jul 28 – Aug 18 |
| Broccoli | Mar 12 – Mar 26 | Apr 23 – May 7 | — | Jun 30 – Jul 21 |
| Cabbage | Mar 12 – Mar 26 | Apr 16 – Apr 30 | — | Jun 30 – Jul 21 |
| Cauliflower | Mar 12 – Mar 26 | Apr 23 – May 7 | — | Jun 30 – Jul 21 |
| Okra | Mar 26 – Apr 9 | May 28 – Jun 11 | May 28 – Jun 11 | — |
| Basil | Mar 26 – Apr 9 | May 14 – May 28 | — | — |
| Peas | — | — | Mar 26 – Apr 16 | Jul 14 – Aug 4 |
| Spinach | — | — | Mar 26 – Apr 16 | Aug 11 – Sep 1 |
| Radishes | — | — | Apr 2 – May 14 | Aug 25 – Sep 15 |
| Cucumbers | Apr 9 – Apr 16 | May 21 – May 28 | May 14 – May 28 | Jul 21 – Aug 4 |
| Zucchini & Summer Squash | Apr 9 – Apr 16 | — | May 14 – May 28 | Jul 28 – Aug 11 |
| Winter Squash & Pumpkins | Apr 9 – Apr 16 | — | May 14 – May 28 | — |
| Melons & Watermelon | Apr 9 – Apr 16 | May 21 – Jun 4 | — | — |
| Carrots | — | — | Apr 16 – May 14 | Jul 14 – Jul 28 |
| Beets | — | — | Apr 16 – May 14 | Jul 28 – Aug 11 |
| Potatoes | — | — | Apr 16 – May 7 | — |
| Swiss Chard | — | — | Apr 23 – May 21 | Jul 28 – Aug 11 |
| Cilantro | — | — | Apr 23 – May 14 | Aug 11 – Sep 1 |
| Green Beans | — | — | May 14 – Jun 4 | Jul 21 – Aug 4 |
| Sweet Corn | — | — | May 14 – May 28 | — |
| Sweet Potatoes | — | May 21 – Jun 11 | — | — |
| Garlic | — | — | — | Sep 22 – Oct 27 |
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 2nw, WY weather station, 2 km away (elevation 4,482 ft (1,366 m)).
Frost dates near Guernsey
- Hartville May 11 · Oct 3
- Fort Laramie May 14 · Sep 26
- Wheatland May 19 · Sep 22
- Jay Em May 23 · Sep 20
- Glendo May 9 · Oct 5
- Lingle May 20 · Sep 22
- Veteran May 15 · Sep 27
- Yoder May 15 · Sep 27
- Torrington May 11 · Sep 29
- Manville May 23 · Sep 20
Frequently asked questions
When is the last frost in Guernsey, WY?
The median last spring frost in Guernsey, WY is May 7. There is still about a 10% chance of frost after May 21, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Guernsey, WY?
The median first fall frost is October 6, with about a 10% chance of frost before September 23.
How long is the growing season in Guernsey, WY?
About 152 days between the median last spring frost and first fall frost.
What planting zone is Guernsey, WY?
Guernsey, WY is in USDA hardiness zone 5a.