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Longmont (CO) Weather and Climate: A Comprehensive Guide

The climate in Longmont is marked by big temperature swings throughout the year. Temperatures range from very warm during the warmest months to cold in the cooler months. It maintains relatively low levels of precipitation throughout the seasons. Let’s explore the climate details in depth to provide you with a complete overview.

Average maximum day and minimum night temperature

In Longmont, temperatures differ significantly between summer and winter months. On average, daytime temperatures range from a very warm 32°C in July to a chilly 6°C in December.

Nighttime temperatures can drop, with average lows reaching -10°C in December. Check out our detailed temperature page for more information.

Temperature ranges by month

Precipitation and rainy days

Longmont's climate is marked by below-average rain/snowfall, accumulating 363 mm of precipitation yearly. The seasons in Longmont, bring significant changes in precipitation. The wettest month, May, receives moderate rainfall, with an average of 62 mm of precipitation. This rainfall is distributed across 12 rainy days.

In contrast, the driest month, January, experiences much less snow/rainfall, totaling 9.5 mm over 4 snowy/rainy days. These distinct seasonal differences provide diverse experiences throughout the year. For more details, please visit our Longmont Precipitation page.

The mean monthly precipitation over the year, including rain, hail and snow

Sunshine over the year

In Longmont, summer days are longer and more sunny, with daily sunshine hours peaking at 10.8 hours in July. As the darker season arrives, the brightness of the sun becomes less. November sees a soft sun for only 6.5 hours per average day. Visit our detailed sunshine hours page for more information.

Monthly hours of sunshine

Data from: Denver, the United States of America (50 KM, 31 Miles).

Daily hours of sunshine

Data from: Denver, the United States of America (50 KM, 31 Miles).

Forecast for Longmont (CO)

Sun   Dec 22
10°C | 2°C
E 3 m/s
broken clouds and no rain

broken clouds and no rain

Mon   Dec 23
13°C | 3°C
E 3 m/s
broken clouds and no rain

broken clouds and no rain

Tue   Dec 24
13°C | 1°C
SE 3 m/s
partly cloudy and no rain

partly cloudy and no rain

The best time of year to visit Longmont in the United States of America

Other facts from our historical weather data:
  • When is summer in Longmont?
    The hottest season / summer takes place in June, July, August and September.
  • Does Longmont have a dry season?
    Yes, the months of January, February and November are very dry.
  • Which is the warmest month in Longmont?
    July has an average maximum temperature of 32°C and is the warmest month of the year.
  • Which is the coldest month in Longmont?
    The coldest month is December with an average maximum temperature of 6°C.
  • Which is the wettest month in Longmont?
    May tops the wettest month list with 62 mm of rainfall.
  • Which is the driest month in Longmont?
    January is the driest month with 10 mm of precipitation.
  • Which is the sunniest month in Longmont?
    July is the sunniest month with an average of 323 hours of sunshine.

  • No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.