Longmont weather by month
Average highs run from 44°F in January to 91°F in July, and January nights average 14°F. It gets 15 inches of rain and melted snow a year and 93 inches of snow. Expect about 49 days a year at 90°F or hotter. Nights drop below freezing about 178 times a year. The most comfortable months are June and September.
Best time to visit Longmont
For comfortable weather, go in June and September. In those months the average high stays between 62°F and 86°F, nights average 42°F or warmer, and rain stays under 4.5 inches for the month.
Month by month
| Month | High | Low | Precip. | Snow | Wet days | Days 90°F+ | Nights below 32°F | Feels |
|---|---|---|---|---|---|---|---|---|
| January | 45°F | 14°F | 0.6 in | 11.3 in | 2 | 0 | 31 | cold |
| February | 47°F | 17°F | 0.6 in | 15.0 in | 2 | 0 | 28 | cold |
| March | 57°F | 26°F | 1.2 in | 15.7 in | 3 | 0 | 27 | cool |
| April | 63°F | 32°F | 2.0 in | 14.7 in | 5 | 0 | 16 | mild days, chilly nights |
| May | 73°F | 41°F | 2.0 in | 2.0 in | 6 | 1 | 3 | mild days, chilly nights |
| June | 84°F | 51°F | 1.8 in | 0.0 in | 5 | 9 | 0 | warm |
| July | 91°F | 55°F | 1.7 in | 0.0 in | 3 | 17 | 0 | hot |
| August | 88°F | 54°F | 2.0 in | 0.0 in | 3 | 15 | 0 | hot |
| September | 80°F | 46°F | 1.3 in | 1.0 in | 4 | 6 | 2 | warm |
| October | 66°F | 33°F | 1.0 in | 7.0 in | 3 | 0 | 15 | mild days, chilly nights |
| November | 54°F | 24°F | 0.8 in | 13.1 in | 3 | 0 | 27 | cool |
| December | 45°F | 15°F | 0.5 in | 13.0 in | 1 | 0 | 31 | cold |
| Year | 66°F avg | 34°F avg | 15.2 in | 92.8 in | 40 | 49 | 178 |
"Wet days" are days with at least 0.1 inch of precipitation. "Feels" is a plain-language label for the average high. Normals for 1991-2020 from NOAA NCEI, station Longmont 2 ESE, CO (USC00055116), 1.2 miles from the city center; snowfall from Boulder, CO. Averages describe typical conditions, not a forecast.
Sunrise, sunset and daylight in Longmont
The shortest day is December 21, with 9h 18m of daylight; the longest is June 21, with 15h 02m. The earliest sunset comes around December 1 (4:34 pm) and the latest around June 21 (8:33 pm). The sun sets after 8 pm on 99 days a year.
| On the 15th of | Sunrise | Sunset | Daylight |
|---|---|---|---|
| January | 7:21 am | 4:59 pm | 9h 38m |
| February | 6:53 am | 5:36 pm | 10h 42m |
| March | 7:11 am | 7:07 pm | 11h 55m |
| April | 6:22 am | 7:39 pm | 13h 17m |
| May | 5:44 am | 8:09 pm | 14h 24m |
| June | 5:30 am | 8:31 pm | 15h 01m |
| July | 5:44 am | 8:28 pm | 14h 44m |
| August | 6:12 am | 7:56 pm | 13h 45m |
| September | 6:41 am | 7:08 pm | 12h 27m |
| October | 7:11 am | 6:20 pm | 11h 09m |
| November | 6:46 am | 4:43 pm | 9h 57m |
| December | 7:15 am | 4:35 pm | 9h 19m |
Calculated for 2026 at the center of Longmont with NOAA's solar equations, in local clock time (Mountain Time, including daylight saving time where it applies). Times shift by a minute or two from year to year.
Is Longmont getting warmer?
The last 10 years averaged 1.9°F warmer than the 20th century. See the climate stripes for Longmont.Frequently asked questions
What is the warmest month in Longmont?
July is the warmest month, with an average high of 91°F and an average low of 55°F (NOAA 1991-2020 normals).
What is the coldest month in Longmont?
January is the coldest, with average lows of 14°F and highs of 45°F.
What is the rainiest month in Longmont?
April gets the most precipitation, 2.0 inches on average. December is the driest at 0.5 inches.
Does it snow in Longmont?
Yes. Longmont averages 93 inches of snow a year.
When is the best time to visit Longmont?
For comfortable weather, June and September. Those months average highs between 62 and 86°F with lows of 42°F or more and modest rain.
Thinking of moving to Longmont?
See what homes, rent and everyday prices cost, who lives there and how it compares with nearby cities on the full Longmont profile.
Compare the weather: Longmont vs Boulder, Longmont vs Loveland, Longmont vs Broomfield, Longmont vs Thornton.