Alamosa, Colorado climate: Normal weather by month, frost dates and records
Alamosa's normal year runs from −1°F January nights to 83°F July afternoons, with 7.4 inches of precipitation and 28 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 5.7°C, January lows of −18°C, July highs of 29°C, 188 mm of precipitation a year.
- NOAA stationAlamosa-Bergman Field
- Station IDUSW00023061
- Location37.44°N 105.86°W
- Elevation7,533 ft (2,296 m)
- From the center3 miles
- Population9,906
On October 23, the normal high in Alamosa is 60°F and the normal low 22°F, and the chance of measurable rain or snow is 14%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Alamosa.
- Jan 35° -1°
- Feb 41° 7°
- Mar 53° 18°
- Apr 60° 25°
- May 70° 34°
- Jun 80° 41°
- Jul 83° 47°
- Aug 81° 46°
- Sep 74° 37°
- Oct 63° 25°
- Nov 49° 12°
- Dec 35° 1°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Alamosa each month?
July is the warmest month, with normal highs of 83°F; January the coldest, with normal lows of −1°F. The most precipitation falls in August (1.29 in), the least in February (0.28 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 35°F | −1°F | 16.8°F | 0.32 | 4.5 | 4 | <1 | 31 | 9 h 50 min |
| February | 41°F | 7°F | 24.3°F | 0.28 | 4.1 | 4 | <1 | 28 | 10 h 50 min |
| March | 53°F | 18°F | 35.2°F | 0.54 | 4.3 | 5 | <1 | 30 | 11 h 50 min |
| April | 60°F | 25°F | 42.6°F | 0.57 | 3.5 | 5 | <1 | 27 | 13 h 10 min |
| May | 70°F | 34°F | 51.7°F | 0.60 | 0.8 | 6 | <1 | 13 | 14 h 10 min |
| June | 80°F | 41°F | 60.6°F | 0.43 | 0.0 | 4 | 1 | 2 | 14 h 40 min |
| July | 83°F | 47°F | 65.3°F | 1.04 | 0.0 | 8 | 2 | <1 | 14 h 30 min |
| August | 81°F | 46°F | 63.2°F | 1.29 | 0.0 | 10 | <1 | <1 | 13 h 40 min |
| September | 74°F | 37°F | 55.9°F | 0.98 | 0.5 | 7 | <1 | 8 | 12 h 30 min |
| October | 63°F | 25°F | 43.8°F | 0.65 | 2.2 | 5 | <1 | 26 | 11 h 20 min |
| November | 49°F | 12°F | 30.3°F | 0.37 | 3.4 | 4 | <1 | 30 | 10 h 10 min |
| December | 35°F | 1°F | 18.1°F | 0.34 | 4.6 | 4 | <1 | 31 | 9 h 40 min |
| Year (annual) | 60°F | 24°F | 42.3°F | 7.41 | 27.9 | 65 | 4 | 226 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 2°C | −18°C | −8.4°C | 8 mm | 11 cm |
| February | 5°C | −14°C | −4.3°C | 7 mm | 10 cm |
| March | 12°C | −8°C | 1.8°C | 14 mm | 11 cm |
| April | 16°C | −4°C | 5.9°C | 14 mm | 9 cm |
| May | 21°C | 1°C | 10.9°C | 15 mm | 2 cm |
| June | 27°C | 5°C | 15.9°C | 11 mm | 0 cm |
| July | 29°C | 8°C | 18.5°C | 26 mm | 0 cm |
| August | 27°C | 8°C | 17.3°C | 33 mm | 0 cm |
| September | 24°C | 3°C | 13.3°C | 25 mm | 1 cm |
| October | 17°C | −4°C | 6.6°C | 17 mm | 6 cm |
| November | 9°C | −11°C | −0.9°C | 9 mm | 9 cm |
| December | 2°C | −17°C | −7.7°C | 9 mm | 12 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00023061; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Alamosa?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, June has the fewest days with rain (4).
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.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00023061.
When is the last frost in Alamosa?
In Alamosa, the last spring frost (32°F) comes after June 7 in half of years and after June 24 in one year in ten; the first autumn frost comes before September 15 in half of years and before September 4 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- June 71 year in 10 after June 24; 9 in 10 after May 24
- First autumn frost, half of years before
- September 151 year in 10 before September 4; 9 in 10 before September 26
NOAA puts the median frost-free season at 98 days, and the season without a hard freeze (28°F) at 124 days.
A hard freeze (28°F) comes after May 23 in half of springs and before September 25 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Alamosa in zone 4b in ZIP code 81101, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Alamosa's NOAA station is in zone 4b: the coldest night of a typical year reaches −22°F (30 complete years).
Frost dates for every NOAA station in Colorado · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00023061; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Alamosa?
In a normal year in Alamosa, 4 days a year reach 90°F, 226 nights fall to 32°F or colder and 65 days bring measurable precipitation.
- Days at 90°F or more
- 4a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 226a normal year
- Days that stay below freezing
- 34high of 32°F or less
- Days with 0.01 inch of precipitation
- 65a normal year
- Days with 1 inch of snow or more
- 9a normal year
The highest temperature in Alamosa's official record (kept by the National Weather Service since 1906) is 96°F, on July 5, 1989; the lowest is −50°F, on January 28, 1948.
The wettest calendar year on that record is 1969, with 11.55 in; the snowiest season is 1972–73, with 97.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00023061; records: ACIS (NOAA Regional Climate Centers), NWS threaded record ALSthr. Records use complete months only; a month missing more than three days is left out.
How humid and windy is Alamosa, and how clear are its skies?
The summer (June-August) dew point averages 42°F. The muggiest month is July, with an average dew point of 47°F; the driest air comes in December (5°F). April is the windiest month (9.8 mph on average), and June has the most clear or nearly clear hours (89%).
| Month | Dew point | Humidity | Afternoon humidity | Wind | Clear or few clouds | Overcast |
|---|---|---|---|---|---|---|
| January | 8°F | 67% | 41% | 5.4 mph | 77% | 12% |
| February | 13°F | 54% | 29% | 7.8 mph | 77% | 10% |
| March | 17°F | 44% | 21% | 9.5 mph | 74% | 10% |
| April | 22°F | 40% | 19% | 9.8 mph | 76% | 7% |
| May | 30°F | 40% | 18% | 9.2 mph | 85% | 3% |
| June | 38°F | 43% | 19% | 7.7 mph | 89% | 2% |
| July | 47°F | 57% | 29% | 6.4 mph | 74% | 8% |
| August | 42°F | 55% | 26% | 6.1 mph | 80% | 7% |
| September | 30°F | 49% | 21% | 6.9 mph | 82% | 6% |
| October | 20°F | 55% | 26% | 6.3 mph | 81% | 9% |
| November | 10°F | 61% | 34% | 5.4 mph | 81% | 10% |
| December | 5°F | 67% | 42% | 4.7 mph | 81% | 9% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00023061. Monthly averages of all hours; afternoon humidity at 3 p.m. local standard time; sky as the share of hours NOAA's observations rate clear or few clouds (a dash where NOAA publishes no sky value).
How sunny is Alamosa?
Over a year 83% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Alamosa, 5.3 kWh per square metre a day. October is the sunniest month (86%) and April the cloudiest (80%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 85% | 3.1 |
| February | 85% | 4.2 |
| March | 81% | 5.2 |
| April | 80% | 6.3 |
| May | 82% | 7.2 |
| June | 85% | 7.8 |
| July | 80% | 6.9 |
| August | 82% | 6.4 |
| September | 86% | 5.7 |
| October | 86% | 4.5 |
| November | 85% | 3.3 |
| December | 83% | 2.7 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Alamosa need?
A normal year in Alamosa brings 8,321 heating degree days, 55% more than the median U.S. place (5,373), and 71 cooling degree days, 92% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,528 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,493 | 0 |
| February | 1,140 | 0 |
| March | 925 | 0 |
| April | 672 | 0 |
| May | 413 | 0 |
| June | 144 | 10 |
| July | 34 | 43 |
| August | 74 | 17 |
| September | 275 | 1 |
| October | 657 | 0 |
| November | 1,041 | 0 |
| December | 1,454 | 0 |
| Year (annual) | 8,321 | 71 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00023061. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Alamosa been warmer than normal lately?
2025 averaged 45.1°F, 2.8°F above the 1991-2020 normal of 42.3°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 44.2°F | +1.9°F | 5.66 | 17.8 |
| 2022 | 43.0°F | +0.7°F | 9.97 | 23.6 |
| 2023 | 43.1°F | +0.9°F | 4.44 | 21.8 |
| 2024 | 44.7°F | +2.4°F | 11.36 | 38.3 |
| 2025 | 45.1°F | +2.8°F | 7.69 | 19.8 |
Over 76 complete years from 1948 to 2025, the station's annual mean temperature rose at a fitted 3.5°F per century (+0.20°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00023061; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Alamosa's climate compare?
Alamosa is warmer than 24 of the other 124 places with their own NOAA record in Colorado, and wetter than 1. Across the 7,247 U.S. stations with normals, its annual mean of 42.3°F is warmer than 10%.
In the Köppen classification computed from these normals, Alamosa is BSk: cold semi-arid steppe. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Alamosa share this climate record?
Alamosa East 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.
- Alamosa East, CO1,404 people · 3 mi NE
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
What do Alamosa's other NOAA stations record?
One more NOAA station keeps 1991-2020 normals in or near Alamosa. This page uses Alamosa-Bergman Field; the other differs by site and elevation:
| Station | From the center | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Alamosa (1 mi E) USC00050128 | 1 mi E | 7,540 ft | 42.6°F | 0°F | 83°F | 7.3 | 30 | May 30 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Alamosa's climate
What is the coldest month in Alamosa?
January, with a normal high of 35°F and a normal low of −1°F. The warmest is July (83°F by day, 47°F at night).
Does it snow in Alamosa?
Yes: 28 inches in a normal year, falling on 22 days with 0.1 inch or more, the most in December (4.6 inches).
What is the rainiest month in Alamosa?
August, with 1.29 in of precipitation in a normal year; the driest is February with 0.28 in.
What plant hardiness zone is Alamosa in?
The USDA's 2023 map puts Alamosa in zone 4b in ZIP code 81101, the nearest ZIP area. By the same method at Alamosa's NOAA station, the coldest night of a typical year reaches −22°F (30 years, 1991-2020): zone 4b.
How late can frost come in Alamosa?
In half of years the last 32°F night comes after June 7; in one year in ten it comes after June 24. Waiting until June 24 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Alamosa in OctoberThis month day by day, its records and recent years
- Colorado climateThe statewide normals and every place in the state
- Waverly (1 mi W), CO9 miles from this station, 40.4°F a year
- Blanca, CO16 miles from this station, 43.5°F a year
- Manassa, CO19 miles from this station, 43.8°F a year
- Monte Vista, CO21 miles from this station, 40.4°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made