Best Time for Outdoor Projects in Wyoming

Wyoming weather and outdoor projects

Wyoming is high, dry and windy. Cheyenne and Casper sit above 5,000 feet, with cool nights even in summer, cold winters and some of the strongest winds in the lower 48. The frost-free season is short in much of the state.

July and August are the most reliable months for staining, painting and concrete. Wind is often the main limit for spraying and for blowing dust onto wet finishes, so pick calm mornings. Strong sun at high elevation fades finishes quickly, and big day-to-night swings mean cold nights after warm afternoons.

Frost dates in Wyoming

In Cheyenne, the median last spring freeze (32°F) is around May 12 and the median first fall freeze is around October 1, a frost-free season of about 141 days.

In Casper, the median last spring freeze (32°F) is around May 26 and the median first fall freeze is around September 22, a frost-free season of about 117 days.

How Wyoming compares with other states

Cheyenne has the 2nd-shortest frost-free season of the 50 state main stations (141 days). Cheyenne has the 3rd-most freezing nights of the 50 state main stations (170 a year). Cheyenne is tied for the 6th-shortest deck staining season of the 50 state main stations (3 good months).

Best time to stain a deck in Wyoming

In Cheyenne, the most reliable months are June–August. May and September can also work on the right days (average highs May 64°F, Sep 73°F). November–April is too cold, with average highs around 45°F. In October, nights average about 34°F, too cold for the coating to dry and cure overnight. In May and September, nights average about 43°F, so finish early on mild days and check the overnight low.

In Casper, the most reliable months are August. June–July and September can also work on the right days (average highs Jun 80°F, Jul 89°F, Sep 76°F). November–March is too cold, with average highs around 40°F. In April–May and October, nights average about 32°F, too cold for the coating to dry and cure overnight. In June and September, nights average about 44°F, so finish early on mild days and check the overnight low. July is hot, with highs near 89°F, so start early and keep out of full afternoon sun.

Deck staining forecast →

Best time to paint outside in Wyoming

In Cheyenne, the most reliable months are June–September. May and October can also work on the right days (average highs May 64°F, Oct 59°F). November–March is too cold, with average highs around 43°F. In April, nights average about 31°F, too cold for the coating to dry and cure overnight. In May and October, nights average about 37°F, so finish early on mild days and check the overnight low.

In Casper, the most reliable months are June and August. May, July and September can also work on the right days (average highs May 67°F, Jul 89°F, Sep 76°F). November–March is too cold, with average highs around 40°F. In April and October, nights average about 30°F, too cold for the coating to dry and cure overnight. In May and September, nights average about 40°F, so finish early on mild days and check the overnight low. July is hot, with highs near 89°F, so start early and keep out of full afternoon sun.

Exterior painting forecast →

Best time to pour concrete in Wyoming

In Cheyenne, the most reliable months are June–September. May can also work on the right days (average highs May 64°F). October–April averages about 23 nights a month at or below 32°F, so fresh concrete needs blankets or heated enclosures. May brings about 5 freezing nights a month, so pick a mild spell and keep curing blankets on hand.

In Casper, the most reliable months are June–August. May and September can also work on the right days (average highs May 67°F, Sep 76°F). October–April averages about 25 nights a month at or below 32°F, so fresh concrete needs blankets or heated enclosures. May and September bring about 5 freezing nights a month, so pick a mild spell and keep curing blankets on hand.

Concrete pouring forecast →

Best time to seal a driveway in Wyoming

In Cheyenne, the most reliable months are July–August. June and September can also work on the right days (average highs Jun 77°F, Sep 73°F). October–April is too cold, with average highs around 47°F. In May, nights average about 40°F, too cold for the coating to dry and cure overnight. In June and September, nights average about 48°F, so finish early on mild days and check the overnight low.

In Casper, the most reliable months are July. June and August–September can also work on the right days (average highs Jun 80°F, Aug 87°F, Sep 76°F). October–April is too cold, with average highs around 45°F. In May, nights average about 37°F, too cold for the coating to dry and cure overnight. In June and August–September, nights average about 46°F, so finish early on mild days and check the overnight low.

Driveway sealing forecast →

Best time to fertilize or treat a lawn in Wyoming

In Cheyenne, the most reliable months are May–September. April and October can also work on the right days (average highs Apr 55°F, Oct 59°F). November–March is too cold, with average highs around 43°F. April and October are cool, with highs around 57°F, so choose the warmest afternoons.

In Casper, the most reliable months are May–June and September. April, July–August and October can also work on the right days. November–March is too cold, with average highs around 40°F. April and October are cool, with highs around 58°F, so choose the warmest afternoons. July–August is hot, with highs near 88°F, so start early and keep out of full afternoon sun.

Lawn fertilizer forecast →

How the weather differs across Wyoming

Of the places above, Cheyenne has the most good months for staining, painting and concrete combined (11 job-months), and Casper has the fewest (6).

Monthly weather in Cheyenne

*Days with 0.1 inch of rain or more; column notes.

Monthly weather in Casper