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.

Frost dates matter for concrete, which must not freeze in its first 48 hours, for paint and caulk that need nights above their minimum, and for lawn care, since crabgrass preventer goes down as the soil warms in spring. See how late in fall you can stain, paint or seal.

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. 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. 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.

Check this week’s hour-by-hour verdict with the 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. 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. 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.

Check this week’s hour-by-hour verdict with the 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. 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. 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.

Check this week’s hour-by-hour verdict with the 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. 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. 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.

Check this week’s hour-by-hour verdict with the 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. 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.

Check this week’s hour-by-hour verdict with the 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). If you live between them, expect something in between, and higher ground to be cooler with a shorter season.

Monthly weather in Cheyenne

*Days with at least 0.1 inch of rain or melted snow. Freezing nights: average nights a month at or below 32°F. Humidity is calculated from NOAA hourly normal temperature and dew point at 3 PM.

Monthly weather in Casper

Use the averages, then check the forecast

These ratings describe a typical month, not a particular week. A warm spell in a “poor” month can give you a good day, and a wet week can spoil a “good” one. Use this page to plan the season, then check the 7-day forecast for your ZIP code before you buy materials or book help. Each project forecast checks the hours after you finish too: overnight lows, dew and rain that would ruin fresh stain, paint, sealer or concrete.

About this data

Monthly temperatures, rain days, snowfall and freeze dates are NOAA National Centers for Environmental Information (NCEI) U.S. Climate Normals for 1991–2020 at CHEYENNE, CASPER NATRONA CO AP. Ratings apply the same temperature limits as our forecasts (for example, 50°F or warmer for deck stain and driveway sealer, and no freezing nights for new concrete) to the average month. Your product label always takes priority.