Fort Collins weather in September: Fort Collins, Colorado: normal highs, lows, rain and records for September
Fort Collins in September has a normal high of 77°F and a normal low of 48°F, a daily mean of 63°F, falling from 82°F on the 1st to 71°F by the 30th. Measurable precipitation falls on 7 days in a normal September, 1.43 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 25°C and low of 9°C, 36 mm of precipitation and 2 cm of snow in September.
- NOAA stationFort Collins
- Station IDUSC00053005
- Location40.58°N 105.09°W
- Elevation5,004 ft (1,525 m)
- Population170,924
- Jan 45° 18°
- Feb 47° 21°
- Mar 56° 29°
- Apr 63° 35°
- May 71° 44°
- Jun 82° 53°
- Jul 87° 59°
- Aug 85° 57°
- Sep 77° 48°
- Oct 64° 36°
- Nov 53° 26°
- Dec 44° 18°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Fort Collins in September?
The normal high is 77°F and the normal low 48°F, for a daily mean of 62.7°F. September is 8.0°F cooler than August and 12.5°F warmer than October. September is the 4th warmest month of the year in Fort Collins and the 6th wettest. Across the month the normal high falls 11°F, from 82°F on September 1 to 71°F on September 30. From one year to the next September's mean temperature typically moves about 2.4°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 60°F and 65°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 25%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 82°F | 53°F | 25% | 10% |
| September 8 | 80°F | 51°F | 24% | 10% |
| September 15 | 78°F | 48°F | 24% | 11% |
| September 22 | 75°F | 46°F | 23% | 11% |
| September 30 | 71°F | 42°F | 22% | 10% |
Every day of September: normal high, low and chance of precipitation (warmest afternoon September 1, coldest night September 30)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| September 1 | 82°F | 53°F | 25% | 10% | 13 h 10 min |
| September 2 | 82°F | 53°F | 25% | 10% | 13 h 10 min |
| September 3 | 82°F | 52°F | 25% | 10% | 13 h |
| September 4 | 82°F | 52°F | 25% | 10% | 13 h |
| September 5 | 81°F | 52°F | 25% | 10% | 13 h |
| September 6 | 81°F | 52°F | 25% | 10% | 13 h |
| September 7 | 81°F | 51°F | 25% | 10% | 12 h 50 min |
| September 8 | 80°F | 51°F | 24% | 10% | 12 h 50 min |
| September 9 | 80°F | 51°F | 24% | 10% | 12 h 50 min |
| September 10 | 80°F | 50°F | 24% | 10% | 12 h 40 min |
| September 11 | 79°F | 50°F | 24% | 10% | 12 h 40 min |
| September 12 | 79°F | 50°F | 24% | 10% | 12 h 40 min |
| September 13 | 79°F | 49°F | 24% | 11% | 12 h 40 min |
| September 14 | 78°F | 49°F | 24% | 11% | 12 h 30 min |
| September 15 | 78°F | 48°F | 24% | 11% | 12 h 30 min |
| September 16 | 78°F | 48°F | 24% | 11% | 12 h 30 min |
| September 17 | 77°F | 48°F | 24% | 11% | 12 h 30 min |
| September 18 | 77°F | 47°F | 23% | 11% | 12 h 20 min |
| September 19 | 76°F | 47°F | 23% | 11% | 12 h 20 min |
| September 20 | 76°F | 47°F | 23% | 11% | 12 h 20 min |
| September 21 | 76°F | 46°F | 23% | 11% | 12 h 20 min |
| September 22 | 75°F | 46°F | 23% | 11% | 12 h 10 min |
| September 23 | 75°F | 45°F | 23% | 11% | 12 h 10 min |
| September 24 | 74°F | 45°F | 23% | 11% | 12 h 10 min |
| September 25 | 74°F | 44°F | 22% | 11% | 12 h 10 min |
| September 26 | 73°F | 44°F | 22% | 10% | 12 h |
| September 27 | 73°F | 44°F | 22% | 10% | 12 h |
| September 28 | 72°F | 43°F | 22% | 10% | 12 h |
| September 29 | 72°F | 43°F | 22% | 10% | 11 h 50 min |
| September 30 | 71°F | 42°F | 22% | 10% | 11 h 50 min |
- Normal high
- 77°FSeptember average
- Normal low
- 48°FSeptember average
- Precipitation
- 1.43 inmonth total
- Days with precipitation
- 70.01 inch or more
- Snowfall
- 0.7 inmonth total
- Days at 90°F or more
- 2
- Nights at 32°F or colder
- 1
- Daylight
- 13 h 10 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 24
- Days at 80°F or more
- 14
- Sunshine
- 80%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USC00053005; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain or snow in Fort Collins in September?
On a given September day the chance of 0.01 inch or more is 24% on average, highest around September 1 (25%). In all, 1.43 in falls on 7 days of a normal September.
In a normal September in Fort Collins, 2 days reach 90°F, 1 nights fall to freezing and snowfall averages 0.7 inches.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USC00053005.
What are the records for September in Fort Collins?
The warmest September temperature on this station's record (since 1893) is 99°F, on September 2, 2019; the coldest is 18°F, on September 30, 1985. The wettest September brought 7.34 in (1938); the snowiest, 15.0 inches (1971).
The September mean against the 1991-2020 normal of 62.7°F: 2021 66.7°F (+4.0), 2022 66.1°F (+3.4), 2023 65.3°F (+2.6), 2024 67.0°F (+4.3), 2025 64.7°F (+2.0), 2026 68.6°F (+5.9). 6 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 66.7°F | +4.0°F | 0.56 in |
| 2022 | 66.1°F | +3.4°F | 1.22 in |
| 2023 | 65.3°F | +2.6°F | 0.67 in |
| 2024 | 67.0°F | +4.3°F | 0.53 in |
| 2025 | 64.7°F | +2.0°F | 2.33 in |
| 2026 | 68.6°F | +5.9°F | 0.57 in |
Source: records: ACIS, station USC00053005; recent months: ACIS, station USC00053005. Records and recent months use complete months only.
How does September in Fort Collins compare across Colorado?
Across the 125 places PlainClimate covers in Colorado, September normal highs run from 62°F in Leadville to 86°F in Lamar; Fort Collins's is 77°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.
Other months and places
- Fort Collins in August85°F by day, 57°F at night
- Fort Collins in October64°F by day, 36°F at night
- Fort Collins through the yearEvery month, frost dates, records and recent years
- Colorado in SeptemberThe statewide normal and the warmest and coolest places
- Lamar: Colorado's warmest Septembernormal high 86°F