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St. Mary's, CO
Full City Profile · Colorado · Gilpin County County
4.1
/5.0
A
Great
130
Population
90/sq mi density
$78,854
Median Income
$38,148 per capita
$406,900
Home Value
$476,301 Zillow
42°F
Avg Temperature
330 sunny days/yr
A
Overall
4.1 / 5.0
Strong
A+
Economy
4.6 / 5.0
$78,854 median income, 0.0% unemployment
B+
Affordability
3.8 / 5.0
$406,900 home value, /mo rent
B+
Education
3.9 / 5.0
36.0% bachelor's degree or higher
St. Mary's has a cool climate with an average annual temperature of 42°F (6°C). Winters average 26°F in January while summers reach 63°F in July. The area gets 330 sunny days per year. Annual precipitation totals 18.3 inches. The area receives 105.9 inches of snow annually. Air quality is rated Good with a median AQI of 41.
Temperature
26°F Jan (-3°C)
63°F Jul (17°C)
| Annual Average | 42.2°F |
| 22% below US avg | |
| January Average | 26°F (-3°C) |
| July Average | 63°F (17°C) |
| Sunny Days | 330 days/yr |
Geography
| Elevation | 10,051 ft (3,064 m) |
| Area | 1.5 sq mi (3.8 km²) |
| Population Density | 90/sq mi |
| Coordinates | 39.8165°N, 105.6471°W |
| Timezone | America/Denver |
| County | Gilpin County County |
| Nearest Airport | Denver International (DEN) 52 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 41.0 |
| Rating | Good |
Air Pollutants (EPA 2023)
| Ozone (O₃) | 0.0518 ppm |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 6.4 / 100 |
| Social Vulnerability | 12.8 / 100 |
| Community Resilience | 79.3 / 100 |
Hazard Breakdown
| Tornado | Very Low |
| Earthquake | Very Low |
| Wildfire | Relatively Low |
| Flood | Very Low |
| Hail | Relatively Low |
| Strong Wind | Very Low |
| Heat Wave | No Rating |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| Ice Storm | Very Low |
| Drought | No Rating |
| Cold Wave | Very Low |
| Landslide | Relatively Low |
| Volcano | Very Low |
| Avalanche | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 26°F (-3°C) | 1.3 in | |
| February | 24°F (-4°C) | 1.1 in | Coldest, Driest |
| March | 27°F (-3°C) | 1.5 in | |
| April | 33°F (0°C) | 1.9 in | |
| May | 43°F (6°C) | 2.1 in | |
| June | 52°F (11°C) | 1.8 in | |
| July | 63°F (17°C) | 2.3 in | Warmest, Wettest |
| August | 56°F (13°C) | 2.2 in | |
| September | 49°F (10°C) | 1.6 in | |
| October | 40°F (5°C) | 1.2 in | |
| November | 29°F (-2°C) | 1.3 in | |
| December | 25°F (-4°C) | 1.4 in |
St. Mary's has a seasonal temperature swing of 39°F / from 24°F in February to 63°F in July. Total annual precipitation is 19.6 inches, with July being the wettest month (2.3") and February the driest (1.1").