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Will it freeze in Alamosa in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Tonight: 27°F (Thu, Nov 5, 6:00 PM MST to Fri, Nov 6, 6:00 AM MST).
Tonight: forecast low 27°F. Hard freeze.
NWS forecast period: Thu, Nov 5, 6:00 PM MST to Fri, Nov 6, 6:00 AM MST.
7 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 27°F Hard freeze · Mostly Cloudy
- Fri, Nov 6 25°F Hard freeze · Partly Cloudy
- Sat, Nov 7 24°F Hard freeze · Mostly Clear
- Sun, Nov 8 25°F Hard freeze · Mostly Clear
- Mon, Nov 9 27°F Hard freeze · Mostly Clear
- Tue, Nov 10 28°F Hard freeze · Partly Cloudy
- Wed, Nov 11 26°F Hard freeze · 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 Alamosa
The median first fall hard-freeze date (28°F) is September 27, from NOAA’s 1991–2020 Climate Normals at Alamosa 1E. 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 | Jun 4 · Jun 14 · Jun 30 | Aug 19 · Sep 5 · Sep 16 | 81 days |
| 32°F freeze | May 17 · May 30 · Jun 13 | Sep 4 · Sep 17 · Sep 27 | 108 days |
| 28°F hard freeze | May 2 · May 16 · Jun 1 | Sep 16 · Sep 27 · Oct 5 | 132 days |
Average high temperature by month
1991–2020 normals at Alamosa 1E
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 Alamosa, CO come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Alamosa 1E (station USC00050128, elevation 7,540 ft), 1.1 mi from Alamosa. 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 Alamosa
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Salida, CO | 73 mi | May 29 | Sep 20 |
| Cañon City, CO | 76 mi | May 4 | Oct 7 |
| Taos, NM | 77 mi | May 19 | Oct 3 |
| Trinidad, CO | 79 mi | Apr 30 | Oct 15 |
| Pueblo, CO | 88 mi | Apr 30 | Oct 9 |
| Raton, NM | 89 mi | May 19 | Sep 29 |
| Gunnison, CO | 94 mi | Jun 21 | Sep 5 |
| Española, NM | 102 mi | May 11 | Oct 6 |
| Fountain, CO | 106 mi | May 3 | Oct 8 |
| Durango, CO | 111 mi | May 21 | Oct 2 |
Frequently asked questions
When is the last frost in Alamosa?
On average, the last spring frost (32°F) in Alamosa is around May 30. In about 1 year in 10 it comes after June 13, and in 9 years in 10 it comes after May 17.
When is the first frost in Alamosa?
The first fall frost (32°F) usually arrives around September 17. There’s a 10% chance of a freeze by September 4 and a 90% chance by September 27.
Can it frost in Alamosa 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 June 14.
What growing zone is Alamosa?
Alamosa is in USDA Plant Hardiness Zone 4b (average annual extreme minimum temperature −25 to −20°F), based on the 2023 USDA map for ZIP code 81101. See growing zones in Colorado.
More: all Colorado frost dates · Colorado growing zones · frost vs. freeze