Bayo Road · Photo: Clyde Charles Brown · CC BY-SA 4.0Los Alamos’ winters are colder and snowier than most of the U.S.
A typical July afternoon reaches 85°, a January night drops to 19°, and about 42 inches of snow falls in a normal winter.
A year in Los Alamos at a glance
Each month’s typical high and low, and what it brings.
What stands out about Los Alamos’ climate
Compared with towns across the U.S., with Los Alamos’ place in New Mexico beside it.
What a year in Los Alamos feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 162 frost-free days a year
In half of years the last 32° night comes by May 2 and the first by October 12. Frost and day counts come from NOAA’s station at Los Alamos, NM, 2.7 miles from the town’s center, 280 ft higher.
The 2023 USDA map puts Los Alamos’ center in zone 7a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 4°. 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 42 inches of snow a winter
Snow, measured at Los Alamos, NM, falls mostly in January. Precipitation (rain plus melted snow) adds up to 15 inches a year; August is the wettest month and February the driest. Rain or snow falls on about 90 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Los Alamos
94% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Los Alamos, NM.
Living with Los Alamos’ climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
162 frost-free days in zone 7a. The last frost comes by May 2 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 12.
Months with highs of 62–84° and lows of 40° or more: May, June, August and September. 82 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Los Alamos from natural hazards, river flooding is the largest share (47%); heat waves, cold waves, winter storms and ice storms together are 4%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Los Alamos and similar climates
TownRatings has no climate map of the towns around Los Alamos yet.
Climates most like Los Alamos’, 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 |
|---|---|---|---|---|
| Los Alamos, NM | 19° | 85° | 15" | 42" |
| Missoula, MT | 18° | 86° | 14" | 43" |
| Doney Park, AZ | 17° | 86° | 16" | 52" |
| Cimarron Hills, CO | 18° | 85° | 17" | 33" |
| Klamath Falls, OR | 22° | 86° | 14" | 52" |
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 Los Alamos averaged 1.4° warmer than the 1900s. The biggest change is in March (+2.7°).
A bigger shift than in 54% 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 Los Alamos compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Los Alamos’ place among New Mexico’s.
Los Alamos weather by month
Highs, lows and precipitation from NOAA’s grid at Los Alamos’ center; snow, wet days and snow on the ground from Los Alamos, NM. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 42° | 19° | 0.8" | 9.9" | 6 | 20 | 26° – 37° |
| February | 47° | 23° | 0.7" | 8.8" | 7 | 14 | 29° – 41° |
| March | 56° | 29° | 0.8" | 5.9" | 7 | 4 | 38° – 47° |
| April | 63° | 34° | 0.8" | 3.3" | 6 | 0 | 44° – 54° |
| May | 73° | 42° | 1.1" | 0.1" | 7 | 0 | 53° – 64° |
| June | 84° | 52° | 1.1" | 0.0" | 7 | 0 | 63° – 72° |
| July | 85° | 57° | 2.6" | 0.0" | 13 | 0 | 68° – 75° |
| August | 83° | 55° | 2.7" | 0.0" | 15 | 0 | 66° – 73° |
| September | 77° | 48° | 1.7" | 0.0" | 9 | 0 | 57° – 66° |
| October | 65° | 37° | 1.3" | 1.7" | 7 | 1 | 48° – 56° |
| November | 52° | 27° | 0.8" | 4.4" | 5 | 3 | 31° – 46° |
| December | 42° | 19° | 0.9" | 8.0" | 6 | 14 | 26° – 36° |
| Year | 64° | 37° | 15.2" | 42.1" | 90 | 55 |
How much a month can swing
A normal is an average. November swings the most: from 1991 to 2020 its average ranged from 31° to 46°. August is the most reliable, staying within 7°.
Where Los Alamos’ 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 Los Alamos’ center.
- Snow: Los Alamos, NM.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Los Alamos, NM, 2.7 miles from the town’s center, 280 ft higher; 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 Los Alamos’ climate
What is the weather like in Los Alamos?
A typical July afternoon reaches 85°, a January night drops to 19°, and about 42 inches of snow falls in a normal winter. Colder January nights than 65% of U.S. towns; hotter July afternoons than 51% of U.S. towns.
How cold does it get in Los Alamos in winter?
January nights average 19°. About 150 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 26°.
How much snow does Los Alamos get?
About 42 inches in a normal winter at Los Alamos, NM, most of it in January, with snow on the ground about 55 days a year.
How hot does it get in Los Alamos?
July, with a typical high of 85° and a low of 57°. About 5 days a year reach 90° (Los Alamos, NM).
When is the first and last frost in Los Alamos?
In half of years the last spring frost (32°) comes by May 2 and the first fall frost by October 12, about 162 frost-free days, at Los Alamos, NM.
What growing zone is Los Alamos in?
Zone 7a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 4°.
What is the best time of year to visit Los Alamos?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Los Alamos getting warmer?
Yes: 1991–2020 averaged 1.4° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 54% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Los Alamos.
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.