When to Plant Grass Seed in Wyoming

Cool-season lawns dominate Wyoming, and for cool-season seed fall is the better window, with spring the second choice. The dates below are typical crossings from in-state monitoring stations; your city page tracks the live reading.

Best Time to Plant Grass Seed in Wyoming

Cool-season · fall window

August 30

August 6 (coolest parts) to September 10 (warmest)

For cool-season lawns (fescue, bluegrass, ryegrass), fall is the best time to plant grass seed in Wyoming, with spring the second choice: fall seedlings face less weed competition and mature before summer heat. The window opens as 2-inch soil falls back through 70°F, and germination slows sharply once soil drops below 50°F, typically around October 13. Fall seeding and fall pre-emergent are an either/or on the same turf; see pre-emergent timing in Wyoming.

Cool-season · spring window

May 4

April 11 (warmest parts) to May 15 (coolest)

Spring is the second choice: the window opens when soil first holds 50°F and narrows as soil passes 65°F, typically by June 6.

Region	Typical spring window opens	Typical fall window opens	Stations
Eastern Wyoming	May 15	—	2
Central Wyoming	May 4	August 30	2

Fall seeding also needs a stop date: new seedlings want about six weeks of growth before frost arrives. Your city page estimates the last safe seeding date from its nearest station: see when to plant in Cheyenne, when to plant in Casper or when to plant in Laramie. Today's statewide reading is on the Wyoming soil temperature page.

Typical dates are computed from historical 2-inch soil temperature averages at 4 monitoring stations in Wyoming; your own window depends on your nearest station's readings.

Best Time to Plant Grass Seed in Wyoming: Month by Month

Typical 2-inch soil temperature by month across Wyoming, the median of 4 in-state stations with multi-year records, with the seeding verdict for each grass family. Confirm against the current reading on your city page before you put seed down.

Month	Typical 2" soil temp	Cool-season seeding	Warm-season seeding
January	30°F	Dormant	Too cold
February	32°F	Dormant	Too cold
March	36°F	Dormant	Too cold
April	45°F	Too cold	Too cold
May	56°F	Good; fall is better	Too cold
June	69°F	Risky; heat ahead	Prime window
July	77°F	Too hot	Prime window
August	74°F	Soon; still cooling	Too late this year
September	65°F	Prime window	Too late this year
October	49°F	Too cold	Too cold
November	36°F	Dormant	Too cold
December	31°F	Dormant	Too cold