Fort Collins, Colorado climate: Normal weather by month, frost dates and records

What is the weather like in Fort Collins each month?

July is the warmest month, with normal highs of 87°F; December the coldest, with normal lows of 18°F. The most precipitation falls in May (2.72 in), the least in January (0.41 in).

Each month has its own page with the day-by-day normals, the month's records and its recent years:

• Jan
• Feb
• Mar
• Apr
• May
• Jun
• Jul
• Aug
• Sep
• Oct
• Nov
• Dec

When is the best weather to visit Fort Collins?

Normal highs sit between 65°F and 85°F in May, June, August and September. Of those, September has the fewest days with rain (7).

That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.

When is the last frost in Fort Collins?

In Fort Collins, the last spring frost (32°F) comes after May 2 in half of years and after May 14 in one year in ten; the first autumn frost comes before October 7 in half of years and before September 24 in one year in ten.

Last spring frost, half of years after

May 21 year in 10 after May 14; 9 in 10 after April 18

First autumn frost, half of years before

October 71 year in 10 before September 24; 9 in 10 before October 20

NOAA puts the median frost-free season at 157 days, and the season without a hard freeze (28°F) at 179 days.

A hard freeze (28°F) comes after April 20 in half of springs and before October 17 in half of autumns.

The USDA's 2023 Plant Hardiness Zone Map puts Fort Collins in zone 5b across its 5 ZIP code areas (5b in 80525, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, Fort Collins's NOAA station is in zone 6a: the coldest night of a typical year reaches −8°F (30 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.

Frost dates for every NOAA station in Colorado · Frost dates by ZIP code

What hardiness zone is each Fort Collins ZIP code in?

The USDA's 2023 map gives each ZIP code area one zone. Fort Collins's 5 ZIP code areas are all in zone 5b. Each ZIP's frost dates are in the frost tool.

How hot and how cold does it get in Fort Collins?

In a normal year in Fort Collins, 30 days a year reach 90°F (1 of them 100°F or more), 150 nights fall to 32°F or colder and 86 days bring measurable precipitation.

Days at 90°F or more

30a normal year

Days at 100°F or more

1a normal year

Nights at 32°F or colder

150a normal year

Days that stay below freezing

15high of 32°F or less

Days with 0.01 inch of precipitation

86a normal year

Days with 1 inch of snow or more

14a normal year

The highest temperature in this station's record (since 1893) is 103°F, on July 21, 2005; the lowest is −41°F, on February 1, 1951.

The wettest calendar year on that record is 1997, with 25.24 in; the snowiest season is 1979–80, with 114.1 inches.

How sunny is Fort Collins?

Over a year 76% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Fort Collins, 4.6 kWh per square metre a day. September is the sunniest month (80%) and May the cloudiest (69%). Among the 459 U.S. places of 50,000 or more, that ranks tied 276th (with 27 others) in sunshine.

How much heating and cooling does Fort Collins need?

A normal year in Fort Collins brings 5,797 heating degree days, 8% more than the median U.S. place (5,373), and 624 cooling degree days, 31% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,747 growing degree days a year above 50°F.

Has Fort Collins been warmer than normal lately?

2025 averaged 53.0°F, 2.3°F above the 1991-2020 normal of 50.7°F. 4 of the 5 complete years since 2021 ran warmer than the normal.

Over 126 complete years from 1887 to 2025, the station's annual mean temperature rose at a fitted 3.3°F per century (+0.18°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.

Which places near Fort Collins share this climate record?

Laporte has no NOAA station with 1991-2020 normals of its own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.

• Laporte, CO2,123 people · 5 mi NW

Nearby and next

• Fort Collins in OctoberThis month day by day, its records and recent years
• Colorado climateThe statewide normals and every place in the state
• Fort Collins (4 mi E), CO3 miles from this station, 49.3°F a year
• Loveland, CO10 miles from this station, 48.7°F a year
• Buckhorn Mountain (1 mi E), CO11 miles from this station, 46.1°F a year
• Waterdale, CO12 miles from this station, 48.2°F a year
• Compare two placesMonth by month, side by side

Download these normals (CSV) · JSON · How these figures are made