Photo: Jeffrey Beall · CC BY 4.0St. Mary's gets about 214 inches of snow a winter, more than all but 9 U.S. towns
On a normal July day the thermometer tops out near 71°. From frosty January to warm July, readings climb 57°. In July, afternoons here are cooler than in almost every U.S. town. Plan time outside from June to August, when highs sit at 66–71°.
A year in St. Mary's at a glance
Each month’s typical high and low, and what it brings.
What stands out about St. Mary's’ climate
Compared with towns across the U.S., with St. Mary's’ place in Colorado beside it.
What a year in St. Mary's feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 103 frost-free days a year
In half of years the last 32° night comes by June 6 and the first by September 19. Frost and day counts come from NOAA’s station at Cabin Creek, CO, 12 miles from the town’s center, 190 ft lower.
The 2023 USDA map puts St. Mary's’ center in zone 5b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −15°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
About 214 inches of snow a winter
Snow, measured at Winter Park, CO, falls mostly in January, February, March, April and December. Precipitation (rain plus melted snow) adds up to 24 inches a year; April is the wettest month and December the driest. Rain or snow falls on about 124 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in St. Mary's
Nearly all of the work is heating: a normal year has almost no cooling days. Months averaging under 55° run from September through June.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Cabin Creek, CO.
Living with St. Mary's’ climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
103 frost-free days in zone 5b. The last frost comes by Jun 6 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 19.
Months with highs of 62–84° and lows of 40° or more: June, July and August. 0.5 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in St. Mary's from natural hazards, avalanches are the largest share (71%). Normals are averages; the hazards page covers the extremes.
Natural hazards →St. Mary's and similar climates
TownRatings has no climate map of the towns around St. Mary's yet.
Climates most like St. Mary'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 |
|---|---|---|---|---|
| St. Mary's, CO | 14° | 71° | 24" | 214" |
| Incline Village, NV | 22° | 73° | 38" | 179" |
| Ishpeming, MI | 5° | 77° | 33" | 197" |
| Summit Park, UT | 19° | 79° | 30" | 153" |
| South Lake Tahoe, CA | 22° | 81° | 19" | 179" |
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 St. Mary's averaged 1.3° warmer than the 1900s. The biggest change is in March (+2.9°).
A smaller shift than in 53% 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 St. Mary's compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with St. Mary's’ place among Colorado’s.
St. Mary's weather by month
Highs, lows and precipitation from NOAA’s grid at St. Mary's’ center; snow, wet days and snow on the ground from Winter Park, CO. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 31° | 14° | 1.4" | 33.2" | 13 | 31 | 18° – 29° |
| February | 33° | 14° | 1.7" | 30.8" | 11 | 29 | 19° – 30° |
| March | 40° | 19° | 2.3" | 31.9" | 11 | 30 | 25° – 35° |
| April | 46° | 23° | 3.2" | 31.5" | 11 | 25 | 29° – 40° |
| May | 55° | 32° | 2.6" | 11.2" | 10 | 8 | 38° – 48° |
| June | 66° | 40° | 1.6" | 1.0" | 7 | 0 | 49° – 58° |
| July | 71° | 46° | 2.4" | 0.0" | 10 | 0 | 55° – 63° |
| August | 69° | 45° | 2.2" | 0.0" | 12 | 0 | 53° – 61° |
| September | 62° | 38° | 1.8" | 1.3" | 9 | 1 | 45° – 54° |
| October | 50° | 29° | 1.6" | 14.2" | 8 | 8 | 33° – 44° |
| November | 39° | 20° | 1.4" | 26.8" | 11 | 24 | 21° – 37° |
| December | 31° | 14° | 1.4" | 32.1" | 12 | 31 | 17° – 27° |
| Year | 49° | 28° | 23.6" | 214.0" | 124 | 186 |
How much a month can swing
A normal is an average. November swings the most: from 1991 to 2020 its average ranged from 21° to 37°. July is the most reliable, staying within 8°.
Where St. Mary'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 St. Mary's’ center.
- Snow: Winter Park, CO.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Cabin Creek, CO, 12 miles from the town’s center, 190 ft lower; 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 St. Mary's’ climate
What is the weather like in St. Mary's?
A typical July afternoon reaches 71°, a January night drops to 14°, and about 214 inches of snow falls in a normal winter. Colder January nights than 86% of U.S. towns; cooler July afternoons than all but 97 U.S. towns.
How cold does it get in St. Mary's in winter?
December nights average 14°. About 234 nights a year reach 32° or below and 21 reach 0° or below. In the coldest December of the last 30 years the month averaged 17°.
How much snow does St. Mary's get?
About 214 inches in a normal winter at Winter Park, CO, most of it in January, February, March, April and December, with snow on the ground about 186 days a year.
How hot does it get in St. Mary's?
July, with a typical high of 71°. 90° days are rare: none in a normal year at Cabin Creek, CO.
When is the first and last frost in St. Mary's?
In half of years the last spring frost (32°) comes by June 6 and the first fall frost by September 19, about 103 frost-free days, at Cabin Creek, CO.
What growing zone is St. Mary's in?
Zone 5b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −15°.
What is the best time of year to visit St. Mary's?
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 St. Mary's getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 53% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in St. Mary's.
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.