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Will it freeze in Fort Collins in the next 7 nights?
No overnight lows at or below 32°F are forecast in Fort Collins during the next 7 nights in the available NWS frost forecast.
Tonight: forecast low 36°F. Frost possible.
NWS forecast period: Thu, Nov 5, 6:00 PM MST to Fri, Nov 6, 6:00 AM MST.
3 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 36°F Frost possible · Mostly Cloudy
- Fri, Nov 6 34°F Frost possible · Mostly Clear
- Sat, Nov 7 35°F Frost possible · Mostly Clear
- Sun, Nov 8 38°F Above 36°F · Clear
- Mon, Nov 9 38°F Above 36°F · Partly Cloudy
- Tue, Nov 10 38°F Above 36°F · Partly Cloudy
- Wed, Nov 11 37°F Above 36°F · Partly Cloudy
Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.
Frost and freeze probabilities
Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.
These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.
Average first hard freeze in Fort Collins
The median first fall hard-freeze date (28°F) is October 17, from NOAA’s 1991–2020 Climate Normals at Ft Collins. This is the 50% probability date, not a forecast for this year.
| Temperature | Last spring date 90% · 50% · 10% chance of a later freeze | First fall date 10% · 50% · 90% chance of an earlier freeze | Season |
|---|---|---|---|
| 36°F frost possible | May 1 · May 12 · May 26 | Sep 15 · Sep 29 · Oct 11 | 138 days |
| 32°F freeze | Apr 18 · May 2 · May 14 | Sep 24 · Oct 7 · Oct 20 | 157 days |
| 28°F hard freeze | Apr 5 · Apr 20 · May 5 | Oct 2 · Oct 17 · Oct 28 | 179 days |
Average high temperature by month
1991–2020 normals at Ft Collins
Average low temperature by month
Months with lows near or below freezing carry frost risk
Where these frost dates come from
The frost dates for Fort Collins, CO come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Ft Collins (station USC00053005, elevation 5,004 ft), 2.2 mi from Fort Collins. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.
Frost dates near Fort Collins
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Timnath, CO | 5.6 mi | May 3 | Oct 6 |
| Loveland, CO | 9.3 mi | May 10 | Oct 1 |
| Windsor, CO | 9.3 mi | May 3 | Oct 6 |
| Wellington, CO | 11 mi | May 3 | Oct 6 |
| Severance, CO | 11 mi | May 3 | Oct 6 |
| Greeley, CO | 18 mi | May 2 | Oct 8 |
| Johnstown, CO | 19 mi | May 10 | Oct 1 |
| Eaton, CO | 19 mi | May 2 | Oct 8 |
| Berthoud, CO | 19 mi | May 7 | Oct 5 |
| Milliken, CO | 20 mi | May 2 | Oct 8 |
Frequently asked questions
When is the last frost in Fort Collins?
On average, the last spring frost (32°F) in Fort Collins is around May 2. In about 1 year in 10 it comes after May 14, and in 9 years in 10 it comes after April 18.
When is the first frost in Fort Collins?
The first fall frost (32°F) usually arrives around October 7. There’s a 10% chance of a freeze by September 24 and a 90% chance by October 20.
Can it frost in Fort Collins after the last frost date?
Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after May 12.
What growing zone is Fort Collins?
Fort Collins is in USDA Plant Hardiness Zone 5b (average annual extreme minimum temperature −15 to −10°F), based on the 2023 USDA map for ZIP code 80525. See growing zones in Colorado.
More: all Colorado frost dates · Colorado growing zones · UV index today in Fort Collins · frost vs. freeze