Wyoming is known for its cold temperatures and harsh winters, making gardening a challenge in many parts of the state. Wyoming falls between USDA hardiness zones 3b and 6a, where chilly conditions can limit what you can grow.
However, some cities, like Cheyenne, enjoy slightly warmer weather, offering better opportunities for planting. If you’re wondering what will thrive in your garden, learn more about the growing zones across Wyoming and how to create the yard you want.
The hardiness zone map for Wyoming
Wyoming falls within planting zones 3b and 6a.
Do you need help to know more about the USDA Hardiness Zone map? Here’s our guide on How the Hardiness Zone Helps with Your Yard.
Check out the Wyoming growing zones below:
Zone 3b
Zone 3b is the coldest growing zone in Wyoming, with winter temperatures dropping as low as -35 to -30 degrees Fahrenheit. Yellowstone National Park, known for its rugged beauty, falls under this zone, as does Gannett Peak in Sublette County, the highest point in Wyoming.
Counties under zone 3b:
- Albany (small area in the northwest)
- Lincoln (small area in the southwest)
- Park (Northwest corner)
- Sublette small area in the center)
- Teton (North)
Zone 4a
Zone 4a in Wyoming experiences winter temperatures between -30 to -25 degrees Fahrenheit. While still very cold, the winters in this zone are slightly milder compared to the frigid conditions of zone 3b.
Areas like Pinedale, Big Piney, and Boulder in Sublette County, as well as Laramie in Albany County, are located in zone 4a.
Counties under zone 4a:
- Albany (Northwest, center, and southeast areas)
- Carbon (Northeast)
- Johnson (small portion in the northwest)
- Lincoln (Southwest and southeast)
- Niobrara (Northeast)
- Park (Northwest)
- Sublette (Most of it)
- Sweetwater (Northwest)
- Teton (North and center)
- Washakie (small portion in the center)
- Weston County (small portion in the southwest)
Zone 4b
Zone 4b in Wyoming experiences winter temperatures between -25 to -20 degrees Fahrenheit, offering milder winters compared to zones 3b and 4a.
Areas like Upton in Weston County, Moorcroft and Pine Haven in Crook County, and Winchester in Washakie County all fall within this zone. The popular towns of Jackson and Sheridan are also in zone 4b.
Counties under zone 4b:
- Albany (center)
- Big Horn (center)
- Campbell (northeast)
- Carbon (northeast)
- Converse (northeast)
- Crook (half west)
- Fremont (northwest)
- Hot Springs (center)
- Johnson (east area)
- Lincoln (southeast)
- Niobrara (north area)
- Park (half west)
- Sheridan (some areas in the west, east, and center)
- Sublette (small areas on its borders)
- Sweetwater (small areas in the north)
- Teton (most of it)
- Washakie (center)
- Weston (most of it)
Zone 5a
Zone 5a in Wyoming has the mildest winters in the region, with temperatures ranging from -20 to -15 degrees Fahrenheit. Most of Wyoming falls within this growing zone. Cities like Lander, Casper, Rawlins, Rock Springs, Cody, Gillette, and Evanston are all located in zone 5a.
Counties under zone 5a:
- Albany (some areas in the southwest and northeast)
- Big Horn (west; some center and east areas too)
- Campbell (most of it)
- Carbon (most of it)
- Converse (most of it)
- Crook (east)
- Fremont (most of it)
- Goshen (most of it)
- Hot Springs (most of it)
- Johnson (most of it)
- Laramie (southeast corner and borders of the county)
- Natrona (most of it)
- Niobrara (south-central)
- Park (some east areas)
- Platte (most of it)
- Sheridan (most of it)
- Sublette County (small area in the northeast)
- Sweetwater (northeast corner and come center areas)
- Uinta (south and some northeast areas)
- Washakie (southwest and east area)
- Weston (small area in the east)
Zone 5b
Zone 5b in Wyoming experiences winter temperatures with an extreme minimum of -15 to -10 degrees Fahrenheit. Areas like Cokeville and Afton in Lincoln County, and areas in the southern region of Wyoming, fall under this zone. Cheyenne, the state capital, is located in zone 5b.
Counties under zone 5b:
- Albany (southeast)
- Big Horn (A line from north to south in the east)
- Campbell (northwest)
- Carbon (southwest)
- Freemont (small portions in the center area)
- Hot Spring (southeast)
- Jonhson (southwest corner and a little portion in the northwest)
- Laramie (most of it)
- Lincoln (most of it)
- Natrona (southwest)
- Platte (small portions in the south area)
- Sweetwater (south-central)
- Teton (southwest)
- Unita (A parallel line from northwest to southeast)
- Washakie (A line from north to south in the east)
Zone 6a
Zone 6a in Wyoming has winter temperatures that range from -10 to -5 degrees Fahrenheit, making it the warmest growing zone in the state. This zone provides a longer growing season and the most flexibility for gardeners in Wyoming. Alpine Northeast, located in this zone, benefits from milder winters compared to the rest of the state.
- Lincoln (small areas in the southwest)
- Sweetwater (south)
- Uinta (northwest)
FAQ about Wyoming planting zones
What growing zone is Riverton, Wyoming?
Riverton, Wyoming, is located in USDA hardiness zones 4b and 5a.
What growing zone is Thermopolis, Wyoming?
Thermopolis falls within USDA hardiness zone 5a.
What is the best grass seed for Wyoming?
The best grass seed for Wyoming depends on the climate in your specific area. For warm-season grasses, buffalograss and blue grama are excellent choices. For cooler climates, cool-season grasses like Kentucky bluegrass, fine fescue, tall fescue, and perennial ryegrass are ideal.
When to call a pro
Knowing the growing zones in Wyoming helps you understand your lawn needs. By learning about your zone, you can choose the right plants and grasses that are best suited for your area’s climate.
If you need help with your lawn, contact a local lawn care professional. They’re ready to help you achieve the outdoor space you want.
Main Image Credit: Chevsapher | Wikimedia Commons | CC0 1.0
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