Wyoming vegetable planting calendar 2027: frost dates and when to plant
In Wyoming, the average last spring frost is May 12 in Cheyenne (NOAA 1991-2020 normals). Below are planting dates for Cheyenne for 27 common vegetables and herbs, worked out the way the Rowtime app does it: NOAA's average frost dates for the nearest weather station, with the planting rules of state extension guides. Dates are for the 2027 season.
Rowtime: Garden Planner works these dates out for your own ZIP code in Wyoming, shows where each one comes from, and recalculates when a planting slips. Get Rowtime on the App Store.
Dates are estimates. Check your local extension office before you plant, and use your own frost records if you have them. Dates shift by a week or more within a state, so pick the city closest to your conditions.
Cheyenne
When to plant tomatoes in Cheyenne?
In Cheyenne, Wyoming, the average last spring frost is May 12 and the average first fall frost is October 1 (NOAA 1991-2020 normals, CHEYENNE station, 11.5 km from ZIP 82001). For tomatoes, start seeds indoors April 16 to June 22 and plant out seedlings June 2 to July 3, following University of Maryland Extension (Home & Garden Information Center) and Utah State University Extension. Dates are for the 2027 season; sources last checked October 24, 2026.
Frost dates for Cheyenne (82001)
- Last spring frost: May 12 on average, May 26 for a 10% risk of a later frost.
- First fall frost: Oct 1 on average, Sep 18 for a 10% risk of an earlier frost.
- USDA hardiness zone 5b (PRISM 2023 listing).
| Crop | When |
|---|---|
| Beet | Sow outdoors: May 5 to Aug 2 Sow outdoors for fall: Jul 24 to Aug 21 |
| Broccoli | Start seeds indoors: Mar 26 to May 2 Plant out seedlings: Apr 14 to Apr 28 Plant out seedlings for fall: Jul 24 to Aug 21 |
| Cabbage | Start seeds indoors: Mar 19 to Apr 15 Plant out seedlings: Apr 14 to Apr 28 Plant out seedlings for fall: Jul 24 to Aug 21 |
| Carrot | Sow outdoors: May 5 to Jul 13 |
| Cauliflower | Start seeds indoors: Apr 2 to May 2 Plant out seedlings: May 5 to Jul 3 Plant out seedlings for fall: Jun 1 to Jul 1 |
| Cucumber | Sow outdoors: May 19 to Jul 23 |
| Eggplant | Start seeds indoors: May 3 to Jun 1 Plant out seedlings: Jun 2 to Jul 3 |
| Green onion | Plant onion sets: Apr 14 to Apr 28 Plant out seedlings for fall: Jul 24 to Aug 21 |
| Kale | Sow outdoors: Apr 14 to Apr 28 Sow outdoors for fall: Jul 24 to Aug 21 |
| Lettuce | Sow outdoors: May 5 to Jul 13 Sow outdoors for fall: Jul 24 to Aug 21 |
| Melon and watermelon | Sow outdoors: Jun 2 to Jun 23 |
| Okra | Plant out seedlings: Jun 9 to Jul 28 |
| Onion | Plant onion sets: Apr 14 to Apr 28 |
| Pea | Sow outdoors: Apr 14 to Apr 28 |
| Pepper | Start seeds indoors: Apr 16 to May 16 Plant out seedlings: Jun 2 to Jul 3 |
| Potato | Plant seed potatoes: May 5 to Jun 23 |
| Snap bean | Sow outdoors: May 19 to Aug 2 |
| Spinach | Sow outdoors: Apr 14 to Apr 28 Sow outdoors for fall: Jul 24 to Aug 21 |
| Summer squash | Sow outdoors: May 19 to Aug 2 |
| Sweet corn | Sow outdoors: May 19 to Jul 3 |
| Sweet potato | Sprout slips indoors: May 17 to Jun 15 Plant out slips: season too short |
| Tomato | Start seeds indoors: Apr 16 to Jun 22 Plant out seedlings: Jun 2 to Jul 3 |
| Winter squash and pumpkin | Sow outdoors: Jun 2 to Jun 23 |
| Basil | Plant outdoors: Jun 15 to Sep 14 |
| Cilantro | Sow outdoors: Mar 18 to May 15 Sow outdoors for fall: Aug 9 to Aug 23 |
| Dill | Sow outdoors: Apr 30 to May 15 Sow outdoors for fall: Jun 24 to Aug 8 |
| Parsley | Sow outdoors: May 5 to Jul 3 Plant outdoors for fall: Jun 24 to Aug 23 |
Sources
Planting rules, in the order Rowtime tries them here:
- Utah State University Extension, Suggested Vegetable Planting Dates for Utah. Checked October 20, 2026.
- Purdue University Extension, Indiana Vegetable Planting Calendar (HO-186-W). Checked October 20, 2026.
- University of Maryland Extension (Home & Garden Information Center), Vegetable Planting Calendar for Central Maryland. Checked October 24, 2026.
- NC State Extension, Central North Carolina Planting Calendar for Annual Vegetables, Fruits, and Herbs (AG-756-01). Checked October 21, 2026.
Frost dates, locations and zones:
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991-2020 annual/seasonal (freeze probabilities).
- U.S. Census Bureau, 2025 Gazetteer Files: ZIP Code Tabulation Areas.
- PRISM Group, Oregon State University / USDA ARS, 2023 USDA Plant Hardiness Zone Map ZIP code listings. PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed 20 Oct 2026.
How the dates are worked out: a guide's rule such as "two weeks after the last frost" is applied to the station's NOAA date. Purdue's dates are 10% dates, so they are counted from the station's 10% date. When a guide gives no last date, the window closes early enough for the crop's longest days to harvest before the first fall frost. When a guide gives no first date for a fall planting, no fall window is shown. "Season too short" means the guide's window would close before it opens at this station's frost dates.
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