Photo: Quintin Soloviev · CC BY 4.0Alamosa’s winters are colder and snowier than most of the U.S.
A typical July afternoon reaches 82°, a January night drops to 3°, and about 30 inches of snow falls in a normal winter.
A year in Alamosa at a glance
Each month’s typical high and low, and what it brings.
What stands out about Alamosa’s climate
Compared with towns across the U.S., with Alamosa’s place in Colorado beside it.
What a year in Alamosa feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 108 frost-free days a year
In half of years the last 32° night comes by May 30 and the first by September 17. Day counts come from NOAA’s station at Alamosa San Luis Airport, 2.6 miles from the town’s center, at about the same height; frost dates and degree days from Alamosa 1e, CO, 1.1 miles away.
The 2023 USDA map puts Alamosa’s center in zone 4b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −21°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 30 inches of snow a winter
Snow, measured at Alamosa 1e, CO, falls mostly in January. Precipitation (rain plus melted snow) adds up to 8 inches a year; August is the wettest month and February the driest. Rain or snow falls on about 64 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Alamosa
99% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Alamosa 1e, CO.
Living with Alamosa’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
108 frost-free days in zone 4b. The last frost comes by May 30 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Sep 17.
Months with highs of 62–84° and lows of 40° or more: June, July and August. 12 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Alamosa from natural hazards, river flooding is the largest share (48%); heat waves, cold waves, winter storms and ice storms together are 13%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Alamosa and similar climates
TownRatings has no climate map of the towns around Alamosa yet.
Climates most like Alamosa’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Alamosa, CO | 3° | 82° | 8" | 30" |
| Dickinson, ND | 5° | 83° | 16" | 35" |
| Sidney, MT | 4° | 85° | 15" | 30" |
| Rock Springs, WY | 9° | 87° | 9" | 31" |
| Aberdeen, SD | 3° | 84° | 22" | 43" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Alamosa averaged 1.4° warmer than the 1900s. The biggest change is in March (+3.2°).
A bigger shift than in 56% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Alamosa compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Alamosa’s place among Colorado’s.
Alamosa weather by month
Highs, lows and precipitation from NOAA’s grid at Alamosa’s center; snow, wet days and snow on the ground from Alamosa 1e, CO. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 35° | 3° | 0.3" | 6.9" | 4 | 20 | 7° – 29° |
| February | 41° | 10° | 0.3" | 4.2" | 3 | 11 | 16° – 35° |
| March | 52° | 20° | 0.6" | 4.3" | 4 | 2 | 32° – 42° |
| April | 60° | 26° | 0.6" | 4.5" | 4 | 2 | 38° – 48° |
| May | 69° | 35° | 0.7" | 0.8" | 6 | 1 | 48° – 56° |
| June | 79° | 42° | 0.5" | 0.0" | 4 | 0 | 57° – 65° |
| July | 82° | 48° | 1.3" | 0.0" | 11 | 0 | 62° – 68° |
| August | 80° | 47° | 1.5" | 0.0" | 9 | 0 | 60° – 66° |
| September | 74° | 39° | 1.0" | 0.0" | 7 | 0 | 52° – 59° |
| October | 63° | 27° | 0.7" | 2.0" | 4 | 1 | 40° – 50° |
| November | 49° | 15° | 0.4" | 3.1" | 3 | 2 | 24° – 40° |
| December | 36° | 5° | 0.4" | 4.2" | 5 | 12 | 10° – 30° |
| Year | 60° | 26° | 8.4" | 30.0" | 64 | 51 |
How much a month can swing
A normal is an average. January swings the most: from 1991 to 2020 its average ranged from 7° to 29°. August is the most reliable, staying within 6°.
Where Alamosa’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Alamosa’s center.
- Snow: Alamosa 1e, CO (NOAA station in town).
- Frost dates, heating and cooling: Alamosa 1e, CO, 1.1 miles away.
- Freezing nights, 90° and 100° days: Alamosa San Luis Airport, 2.6 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Alamosa’s climate
What is the weather like in Alamosa?
A typical July afternoon reaches 82°, a January night drops to 3°, and about 30 inches of snow falls in a normal winter. Colder January nights than all but 93 U.S. towns; cooler July afternoons than 79% of U.S. towns.
How cold does it get in Alamosa in winter?
January nights average 3°. About 226 nights a year reach 32° or below and 44 reach 0° or below. In the coldest January of the last 30 years the month averaged 7°.
How much snow does Alamosa get?
About 30 inches in a normal winter at Alamosa 1e, CO, most of it in January, with snow on the ground about 51 days a year.
How hot does it get in Alamosa?
July, with a typical high of 82° and a low of 48°. About 4 days a year reach 90° (Alamosa 1e, CO).
When is the first and last frost in Alamosa?
In half of years the last spring frost (32°) comes by May 30 and the first fall frost by September 17, about 108 frost-free days, at Alamosa 1e, CO.
What growing zone is Alamosa in?
Zone 4b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −21°.
What is the best time of year to visit Alamosa?
By one simple rule (highs of 62–84° and lows of 40° or more), June, July and August. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Alamosa getting warmer?
Yes: 1991–2020 averaged 1.4° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 56% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Alamosa.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.