Wyoming Planting Zones by City and ZIP Code
Wyoming runs from zones 4a to 5b; 58% of its ZIPs are 5a, Cheyenne is 5b and Casper is 5a.
Wyoming runs from zones 4a to 5b
The coldest night of the winter averages -30°F to -25°F in the coldest of Wyoming’s ZIP codes and -15°F to -10°F in the warmest. Most of the state is zone 5a.
Planting zones of Wyoming cities
| City | Zone | Coldest night, on average | Since 2012 |
|---|---|---|---|
| Cheyenne82001 | 5b | -15°F to -10°F | same as 2012 |
| Casper82601 | 5a | -20°F to -15°F | same as 2012 |
| Laramie82070 | 4b | -25°F to -20°F | same as 2012 |
| Jackson83001 | 4b | -25°F to -20°F | half a zone colder than 2012 (5a) |
| Sheridan82801 | 5a | -20°F to -15°F | half a zone warmer than 2012 (4b) |
| Rock Springs82901 | 5b | -15°F to -10°F | half a zone warmer than 2012 (5a) |
Tap a ZIP for that address’s frost dates and this month’s jobs.
Find your zone anywhere in Wyoming
A ZIP code or a town gives you its zone, how it moved since 2012, the frost dates at the nearest NOAA station, and the jobs for this month timed from them.
What to plant in Wyoming this month
The calendar for each of Wyoming's main zones, from vegetables to pruning and winter protection, each job tied to the extension page it comes from. Pick a month, or read the whole year below it.
Timed from the median frost dates of the 26 NOAA stations in Wyoming’s zone 5a: last spring frost May 18, first fall frost Sep 25. Your own ZIP’s frost dates move every window, so the ZIP tool times them for you.
Pick a month above to see every job in it.
The year at a glance
- Start vegetable seeds indoorsFeb to May
- Sow vegetables in the gardenApr to May
- Sow the fall vegetable gardenJun to Aug
- Set out transplantsApr to Jun
- Plant trees and shrubsApr 6 to Jun 1 and Sep 11 to Oct 30
- Plant garlicSep 11 to Oct 16
- Plant tulips and other spring bulbsOct 2 to Oct 9
- Divide fall-blooming perennialsApr 27 to Jun 8
- Divide spring and summer-blooming perennialsAug 14 to Sep 25
- Prune trees and summer-flowering shrubs while dormantMar 9 to Apr 20
- Prune spring-flowering shrubs after they bloomMay 4 to Jun 29
- Water evergreens and new plantings until the ground freezesAug 28 to Nov 6
- Mulch perennial crowns once the ground freezesNov 6 to Nov 20
- Pull back the winter mulchMar 30 to Apr 13
- Put hardware cloth around young tree trunksSep 25 to Nov 6
- Dig and store canna, dahlia and gladiolusSep 25 to Oct 2
- Cut back perennials after a hard freezeOct 2 to Oct 30
What changed in Wyoming since 2012
Every ZIP on both mapsCompared ZIP by ZIP from the 2023 and 2012 USDA tables; 191 Wyoming ZIP codes appear in both.
Why Wyoming’s zones moved
Of the cities above, Jackson went from 5a to 4b, Sheridan went from 4b to 5a and Rock Springs went from 5a to 5b.
The USDA explains the national picture: “When compared to the 2012 map, the 2023 version reveals that about half of the country shifted to the next warmer half zone, and the other half of the country remained in the same half zone.” The new map uses 1991 to 2020 and more than 13,000 weather stations, so it draws Wyoming’s hills, valleys and cities more finely than the 2012 map did.
A warmer zone changes which perennials and shrubs come through the winter, not when the garden gets planted; that still follows the frost dates.
Frost dates and seed starting in Wyoming
Wyoming planting zone questions
Planting zones by state
Sources. USDA Plant Hardiness Zone Map, ZIP code tables (2023 and 2012), PRISM Climate Group, Oregon State University; USDA Plant Hardiness Zone Map; USDA Unveils Updated Plant Hardiness Zone Map (USDA Agricultural Research Service, November 15, 2023); NOAA NCEI U.S. Climate Normals 1991-2020, annual/seasonal, by station (v1.0.1); NC State Extension Gardener Plant Toolbox. Zones are read from the PRISM ZIP code tables, read Oct 9, 2026; a ZIP code’s zone is the zone at its center. The calendar’s extension sources are listed on the planting zones page and under each job.