Fort Collins, CO Climate & Monthly Averages
Fort Collins has a semi-arid climate. July is the hottest month, averaging 87° by day; January is the coldest at 38°.
Winter sets the pace in Fort Collins
Cold is the baseline in Fort Collins, not the exception. Night-time lows sit at or below freezing in 5 months of the year, and the warmest month, July, still only averages 87°F (31°C) by day. January runs to 16°F (-9°C) after dark.
July
87° by day 61° at nightJanuary
38° by day 16° at nightThe cold-weather pattern in numbers
July is the warm end of the year, averaging 87°F (31°C) by day and 61°F (16°C) overnight. January sits at the other end of the year: 38°F (4°C) by day, 16°F (-9°C) at night. The gridded 2015-2024 daily record for this location tops out at 100°F (38°C) and bottoms at -28°F (-33°C) - decade extremes, not all-time station records. 3 months average under 20 mm of rain, the longest unbroken stretch running December through January.
Relative humidity averages 56% across the year, drier than all but 10% of the 3496 cities in our dataset. Snow falls on roughly 23 days a year, mostly October through May. Overnight lows average at or below freezing for 5 months, November through March. The wettest month is May (4.1 inches (105 mm) across 13 days) and the driest January.
More climate facts for Fort Collins
- Hottest month: July - highs near 87°F (31°C)
- Coldest month: January - highs near 38°F (4°C)
- Decade extremes (2015-2024): 100°F (38°C) high · -28°F (-33°C) low
- Wettest month: May (13 rainy days) · Sunniest: July (12.9 h sun/day)
- Climate type: semi-arid
- Annual swing: 26°C between the average warmest and coolest month · day to night: 14°C
- Snow: about 23 days a year
- Months averaging 30°C or hotter: 1
- Average humidity: 56%
From snow season to the warmest stretch in Fort Collins
Spring (March through May)
Spring in Fort Collins runs cool rather than cold, with daytime highs averaging 59°F (15°C) and nights around 34°F (1°C); expect showers on roughly 28 days across the season, plus about 8 snowy days. Daylight is generous - around 10.5 hours of sun a day.
Summer (June through August)
Summer brings hot afternoons here - highs near 84°F (29°C), nights near 58°F (15°C), and expect showers on roughly 20 days across the season. Daylight is generous - around 12.6 hours of sun a day.
Fall (September through November)
Through fall, Fort Collins is crisp but comfortable: 65°F (18°C) by day, 40°F (4°C) after dark, and rain comes on about 14 days over the three months, plus about 5 snowy days.
Winter (December through February)
Through winter, Fort Collins is chilly: 40°F (4°C) by day, 18°F (-8°C) after dark, and rain comes on about 13 days over the three months, plus about 10 snowy days.
The coldest and warmest values in the dataset
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ. Need another precipitation unit? Use the rainfall converter.
Planning around winter in Fort Collins
The easier weather window
Aim for September to October and April if you get the choice: temperatures sit either side of the peak heat rather than in it, and highs average 71°F (22°C) against roughly 6 wet days a month. For the same question asked the other way round, see where else is warm in September.
Cold-weather packing
Pack for Fort Collins with light clothing for the warm months, a heavy insulated coat, hat and gloves for winter and rain gear if you travel around May. Even in July, lows of 61°F (16°C) make an extra layer worth the space.
Monthly highs, lows and seasonal change
| Month | High | Low | Rain days | Precipitation | Sunshine | Daylight | Wet-day chance | Humidity |
|---|---|---|---|---|---|---|---|---|
| January | 38° | 16° | 4 | 0.6 in | 7.9 h/day | 9.6 h | 14% | 63% |
| February | 41° | 17° | 5 | 0.9 in | 8.9 h/day | 10.6 h | 17% | 59% |
| March | 51° | 25° | 6 | 1.6 in | 9.8 h/day | 11.8 h | 20% | 58% |
| April | 60° | 33° | 8 | 1.9 in | 10.6 h/day | 13.2 h | 27% | 52% |
| May | 67° | 43° | 13 | 4.1 in | 11.1 h/day | 14.4 h | 43% | 62% |
| June | 81° | 55° | 8 | 1.8 in | 12.8 h/day | 15.1 h | 26% | 54% |
| July | 87° | 61° | 6 | 1.3 in | 12.9 h/day | 14.8 h | 20% | 51% |
| August | 85° | 59° | 6 | 1.0 in | 12.2 h/day | 13.8 h | 19% | 51% |
| September | 80° | 53° | 4 | 0.7 in | 11.0 h/day | 12.4 h | 14% | 47% |
| October | 64° | 39° | 5 | 0.9 in | 9.4 h/day | 11.0 h | 15% | 53% |
| November | 50° | 28° | 5 | 0.8 in | 8.5 h/day | 9.9 h | 17% | 59% |
| December | 40° | 20° | 4 | 0.6 in | 7.6 h/day | 9.3 h | 13% | 59% |
The route from winter to summer, month by month
Each card shows the average high and low. The bar places that month between Fort Collins's coldest night and warmest afternoon.
January
- Rain
- 4 days
- Sunshine
- 7.9 h
- Daylight
- 9.6 h
- Snow
- 3 days
February
- Rain
- 5 days
- Sunshine
- 8.9 h
- Daylight
- 10.6 h
- Snow
- 4 days
March
- Rain
- 6 days
- Sunshine
- 9.8 h
- Daylight
- 11.8 h
- Snow
- 4 days
April
- Rain
- 8 days
- Sunshine
- 10.6 h
- Daylight
- 13.2 h
- Snow
- 3 days
May
- Rain
- 13 days
- Sunshine
- 11.1 h
- Daylight
- 14.4 h
- Snow
- 1 day
June
- Rain
- 8 days
- Sunshine
- 12.8 h
- Daylight
- 15.1 h
July
- Rain
- 6 days
- Sunshine
- 12.9 h
- Daylight
- 14.8 h
August
- Rain
- 6 days
- Sunshine
- 12.2 h
- Daylight
- 13.8 h
September
- Rain
- 4 days
- Sunshine
- 11.0 h
- Daylight
- 12.4 h
October
- Rain
- 5 days
- Sunshine
- 9.4 h
- Daylight
- 11.0 h
- Snow
- 1 day
November
- Rain
- 5 days
- Sunshine
- 8.5 h
- Daylight
- 9.9 h
- Snow
- 3 days
December
- Rain
- 4 days
- Sunshine
- 7.6 h
- Daylight
- 9.3 h
- Snow
- 3 days
Looking for warmer alternatives? Browse warm places by month, or compare Fort Collins's coolest part of the year: January, December, February.
Where Fort Collins sits among other climates
- Afternoons run 14°C above the following night - a bigger day-to-night gap than any other city in our 3496-city dataset.
- Fort Collins averages 49°F (10°C) across the year - cooler than all but 8% of the 3496 cities we track.
- Annual precipitation is 16.2 inches (412 mm) - drier than all but 12% of the 3496 cities we track.
These comparisons use the same ten-year window for every city in the dataset.