Weather in Fort Collins, Colorado
High country wildflowers peak. Day 59 of spring. Read this microseason across nine climate regions →
- TodayMay 16Overcast18%78°55°
- SundayMay 17Heavy Rain51%71°50°
- MondayMay 18Light Snow99%49°37°
- TuesdayMay 19Light Drizzle41%55°35°
- WednesdayMay 20Overcast41%70°44°
- ThursdayMay 21Drizzle46%62°49°
- FridayMay 22Overcast27%73°46°
- PM 2.5
- 5.1 μg/m³
- PM 10
- 6.0 μg/m³
- NO₂
- 8.8 μg/m³
- Ozone
- 85.0 μg/m³
- UV Index
- 0.0 Low
When the dew is on the grass, rain will never come to pass.
- Moonrise
- 11:50 AM
- Moonset
- 2:45 AM
- In sign
- ♊︎ Gemini
High country wildflowers peak
Fort Collins at a glance
- Today vs. normal: 7°F below the seasonal normal for this latitude
- Last frost: April 19 (climatological average for this latitude)
- Microseason: 28 of 72, May 16–20
- Planting window: Direct sow okra, melons, and southern peas. Thin carrot rows.
Right now in the garden
Warm-season window is open
As of May 17, the last spring frost has passed for most years. Transplant tomatoes, peppers, eggplants, basil, and cucurbits (cucumbers, squash, melons) now. Direct-sow beans and corn into warm soil.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | — | — |
| April | lettuce, peas, spinach, radishes | — |
| May | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
July brings Fort Collins its warmest temperatures (~73°F mean) while December delivers the coldest (~31°F). May produces peak rainfall at 2.7 inches, contrasting sharply with January's meager 0.4 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 32° | 0.4″ | 2 |
| February | 34° | 0.5″ | 2 |
| March | 42° | 1.3″ | 3 |
| April | 49° | 2.1″ | 5 |
| May | 58° | 2.7″ | 6 |
| June | 67° | 1.9″ | 4 |
| July | 73° | 1.6″ | 4 |
| August | 71° | 1.4″ | 3 |
| September | 63° | 1.4″ | 3 |
| October | 50° | 1.3″ | 3 |
| November | 39° | 0.7″ | 2 |
| December | 31° | 0.5″ | 2 |
Regional context
Fort Collins falls within a cold semi-arid climate region. This classification connects it with nearby cities that experience similar temperature ranges, seasonal patterns, and growing conditions.
Similar climates: Greeley, CO, Boulder, CO, Longmont, CO, Loveland, CO, Windsor, CO.
Naturalist notes
Late May brings the return of broad-tailed hummingbirds to Fort Collins gardens and mountain meadows.
Ponderosa pine trees begin releasing their pollen around mid-May, dusting surfaces with yellow powder.
Frequently asked
- When does it freeze in Fort Collins?
- Fort Collins typically experiences its last spring frost around mid-April, while the first fall frost arrives around mid-November.
- What is the rainy season in Fort Collins?
- May stands as the wettest month with about 2.7 inches of rain on average, contributing to the city's roughly 16 inches annually.
- What is the warmest month in Fort Collins?
- July typically brings the warmest weather, averaging about 73°F.
- What is the coldest month in Fort Collins?
- December typically delivers the coldest temperatures, averaging about 31°F.
- When can I start a vegetable garden in Fort Collins?
- Cool-season crops (peas, lettuce) can be planted around the last spring frost (mid-April), while warm-season crops (tomatoes, peppers) should wait until 1–2 weeks after.
- How many rainy days does Fort Collins get?
- Fort Collins averages about 37 rainy days per year.
- What hardiness zone is Fort Collins?
- Fort Collins's USDA hardiness zone depends on its lowest average winter temperature. Check the USDA's online lookup with the city ZIP for the current zone designation.
Climate
Fort Collins, Colorado experiences a cold semi-arid climate zone. January temperatures hover near 32°F while July averages 73°F, creating a 41°F seasonal swing.
Throughout the year, Fort Collins receives about 16 inches of precipitation spread over roughly 37 rainy days.
Several factors determine the annual weather patterns: latitude (40.5°N), proximity to large water bodies, and elevation. These elements influence what grows here, when frost occurs, and daily weather conditions.