Greybull, WY frost dates
Last spring frostMay 11median date
First fall frostSep 23median date
Growing season135 daysfrost-free
Hardiness zone4bZone 4b
How Greybull compares
- In 8 years out of 10, the last spring frost in Greybull falls between April 30 and May 24, a 24-day window. The first fall frost falls between September 11 and October 6.
- The median last frost is 10 days earlier than the Wyoming median of May 21.
- Its 135-day growing season is longer than 67% of the 153 Wyoming places with a regular frost season (state median 125 days).
- The last frost is typical for zone 4b, where the median is May 8.
- The weather station records an average of 185 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 30 |
| 50% (median) | May 11 |
| 10% (safe for tender plants) | May 24 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 11 |
| 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 Greybull, WY
Greybull, WY frost dates — last frost May 11, first frost Sep 23, zone 4b. 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: Jul 29 to Aug 26
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 13 to Apr 27Sow outdoors: Apr 13 to Apr 27Plant for fall: Jul 15 to Aug 5
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 27 to May 11Plant for fall: Jun 17 to Jul 8
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 20 to May 4Plant for fall: Jun 17 to Jul 8
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 27 to May 11Plant for fall: Jun 17 to Jul 8
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 1 to Jul 22
Sow outdoors: Mar 30 to Apr 20Plant for fall: Jul 29 to Aug 19
Sow outdoors: Apr 6 to May 18Plant for fall: Aug 12 to Sep 2
Start indoors: Apr 13 to Apr 20Transplant outside: May 25 to Jun 1Sow outdoors: May 18 to Jun 1Plant for fall: Jul 8 to Jul 22
Start indoors: Apr 13 to Apr 20Sow outdoors: May 18 to Jun 1Plant for fall: Jul 15 to Jul 29
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 1 to Jul 15
Sow outdoors: Apr 20 to May 18Plant for fall: Jul 15 to Jul 29
Sow outdoors: Apr 20 to May 11
Sow outdoors: Apr 27 to May 25Plant for fall: Jul 15 to Jul 29
Sow outdoors: Apr 27 to May 18Plant for fall: Jul 29 to Aug 19
Sow outdoors: May 18 to Jun 8Plant for fall: Jul 8 to Jul 22
Sow outdoors: May 18 to Jun 1
Transplant outside: May 25 to Jun 15
Plant for fall: Sep 9 to Oct 14
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Greybull, 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 | Jul 29 – Aug 26 |
| Kale | Mar 16 – Mar 30 | Apr 13 – Apr 27 | Apr 13 – Apr 27 | Jul 15 – Aug 5 |
| Broccoli | Mar 16 – Mar 30 | Apr 27 – May 11 | — | Jun 17 – Jul 8 |
| Cabbage | Mar 16 – Mar 30 | Apr 20 – May 4 | — | Jun 17 – Jul 8 |
| Cauliflower | Mar 16 – Mar 30 | Apr 27 – May 11 | — | Jun 17 – Jul 8 |
| 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 1 – Jul 22 |
| Spinach | — | — | Mar 30 – Apr 20 | Jul 29 – Aug 19 |
| Radishes | — | — | Apr 6 – May 18 | Aug 12 – Sep 2 |
| Cucumbers | Apr 13 – Apr 20 | May 25 – Jun 1 | May 18 – Jun 1 | Jul 8 – Jul 22 |
| Zucchini & Summer Squash | Apr 13 – Apr 20 | — | May 18 – Jun 1 | Jul 15 – Jul 29 |
| 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 1 – Jul 15 |
| Beets | — | — | Apr 20 – May 18 | Jul 15 – Jul 29 |
| Potatoes | — | — | Apr 20 – May 11 | — |
| Swiss Chard | — | — | Apr 27 – May 25 | Jul 15 – Jul 29 |
| Cilantro | — | — | Apr 27 – May 18 | Jul 29 – Aug 19 |
| Green Beans | — | — | May 18 – Jun 8 | Jul 8 – Jul 22 |
| Sweet Corn | — | — | May 18 – Jun 1 | — |
| Sweet Potatoes | — | May 25 – Jun 15 | — | — |
| 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 Greybull, WY weather station, 2 km away (elevation 3,786 ft (1,154 m)).
Frost dates near Greybull
- Basin Apr 28 · Oct 10
- Otto May 12 · Sep 28
- Emblem May 12 · Sep 28
- Shell May 16 · Sep 24
- Manderson Apr 28 · Oct 10
- Burlington May 12 · Sep 28
- Hyattville May 10 · Oct 1
- Lovell May 9 · Sep 29
- Byron May 9 · Sep 29
- Cowley May 9 · Sep 29
Frequently asked questions
When is the last frost in Greybull, WY?
The median last spring frost in Greybull, WY is May 11. There is still about a 10% chance of frost after May 24, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Greybull, WY?
The median first fall frost is September 23, with about a 10% chance of frost before September 11.
How long is the growing season in Greybull, WY?
About 135 days between the median last spring frost and first fall frost.
What planting zone is Greybull, WY?
Greybull, WY is in USDA hardiness zone 4b.