Utah weather and outdoor projects
Utah has a dry climate with hot summers, cold winters and big swings between day and night temperatures. Salt Lake City sits at over 4,000 feet, so nights cool quickly even after warm days. Southern Utah is hotter and drier, while the mountains have a short summer season.
Late spring through early fall is the main window for exterior projects. Strong sun and low humidity make stain and paint dry fast, so avoid midday heat on sunny walls and decks. Summer monsoon storms bring afternoon wind and rain in some years, and winter inversions in the valleys can bring long cold, foggy spells.
Frost dates in Utah
In Salt Lake City, the median last spring freeze (32°F) is around April 8 and the median first fall freeze is around October 31, a frost-free season of about 204 days.
How Utah compares with other states
Salt Lake City has the 3rd-least humid summer afternoons of the 47 state main stations (19% humidity at 3 PM, June–August). Salt Lake City is tied for the 6th-shortest deck staining season of the 50 state main stations (3 good months). Salt Lake City has the 11th-fewest rainy days of the 50 state main stations (45 a year with 0.1 in or more).
| Measure (Salt Lake City) | Value | Rank, highest first |
|---|---|---|
| Deck staining season | 3 good months | 38th of 50 |
| Frost-free season | 204 days | 27th of 50 |
| Freezing nights | 112 a year | 17th of 50 |
| Rainy days | 45 a year with 0.1 in or more | 40th of 50 |
| Days at 90°F or hotter | 62 a year | 13th of 50 |
| Summer afternoons | 19% humidity at 3 PM, June–August | 45th of 47 |
Best time to stain a deck in Utah
In Salt Lake City, the most reliable months are May–June and September. April, August and October can also work on the right days (average highs Apr 62°F, Aug 92°F, Oct 66°F). November–February is too cold, with average highs around 43°F. In March, nights average about 36°F, too cold for the coating to dry and cure overnight. July is hot, with average highs near 94°F and about 24 days a month at 90°F or more, so work early in the day. April is cool, with highs around 62°F, so choose the warmest afternoons. August is hot, with highs near 92°F, so start early and keep out of full afternoon sun. In October, nights average about 44°F, so finish early on mild days and check the overnight low.
Best time to paint outside in Utah
In Salt Lake City, the most reliable months are May–June and September. March–April, August and October can also work on the right days. December–February is too cold, with average highs around 41°F. July is hot, with average highs near 94°F and about 24 days a month at 90°F or more, so work early in the day. In November, nights average about 33°F, too cold for the coating to dry and cure overnight. March is cool, with highs around 55°F, so choose the warmest afternoons. In April and October, nights average about 43°F, so finish early on mild days and check the overnight low. August is hot, with highs near 92°F, so start early and keep out of full afternoon sun.
Best time to pour concrete in Utah
In Salt Lake City, the most reliable months are May–September. April and October can also work on the right days (average highs Apr 62°F, Oct 66°F). November–March averages about 21 nights a month at or below 32°F, so fresh concrete needs blankets or heated enclosures. April and October bring about 3 freezing nights a month, so pick a mild spell and keep curing blankets on hand.
Best time to seal a driveway in Utah
In Salt Lake City, the most reliable months are June–September. May and October can also work on the right days (average highs May 73°F, Oct 66°F). November–March is too cold, with average highs around 46°F. In April, nights average about 42°F, too cold for the coating to dry and cure overnight. In May, nights average about 50°F, so finish early on mild days and check the overnight low. October is cool, with highs around 66°F, so choose the warmest afternoons.
Best time to fertilize or treat a lawn in Utah
In Salt Lake City, the most reliable months are April–June and September–October. March, August and November can also work on the right days (average highs Mar 55°F, Aug 92°F, Nov 51°F). December–February is too cold, with average highs around 41°F. July is hot, with average highs near 94°F and about 24 days a month at 90°F or more, so work early in the day. March and November are cool, with highs around 53°F, so choose the warmest afternoons. August is hot, with highs near 92°F, so start early and keep out of full afternoon sun.
Monthly weather in Salt Lake City
| Month | Avg high | Avg low | Wet days* | Rain | 3 PM humidity | Freezing nights |
|---|---|---|---|---|---|---|
| January | 39°F | 24°F | 5 | 1.4 in | 62% | 27 |
| February | 45°F | 29°F | 4 | 1.3 in | 51% | 21 |
| March | 55°F | 36°F | 5 | 1.8 in | 38% | 12 |
| April | 62°F | 42°F | 6 | 2.2 in | 34% | 4 |
| May | 73°F | 50°F | 5 | 1.8 in | 29% | 0 |
| June | 84°F | 59°F | 3 | 0.9 in | 21% | 0 |
| July | 94°F | 68°F | 2 | 0.5 in | 18% | 0 |
| August | 92°F | 67°F | 2 | 0.6 in | 19% | 0 |
| September | 81°F | 56°F | 3 | 1.1 in | 24% | 0 |
| October | 66°F | 44°F | 4 | 1.3 in | 31% | 3 |
| November | 51°F | 33°F | 4 | 1.3 in | 45% | 17 |
| December | 39°F | 25°F | 5 | 1.4 in | 60% | 27 |
*Days with 0.1 inch of rain or more; column notes.
Source: NOAA NCEI U.S. Climate Normals 1991–2020 for SALT LAKE CITY INTL AP. See how the ratings work and how late in fall you can stain, paint or seal.
Frequently asked questions
When is the best time to stain a deck in Utah?
In Salt Lake City, May–June and September.
When is the last frost in Utah?
Salt Lake City: around April 8.
Can you pour concrete in winter in Utah?
Yes, with cold-weather practices: Salt Lake City averages about 76 freezing nights from December to February, so fresh concrete needs insulated blankets, a heated enclosure or an accelerated mix, and must not freeze in the first 48 hours. Many homeowners wait for spring.
What months are best for sealing a driveway in Utah?
In Salt Lake City, June–September.