Temperature, precipitation, air quality, natural hazards, and monthly weather data.
St. Marys experiences four distinct seasons with an average annual temperature of 53°F (12°C). Winters average 31°F in January while summers reach 74°F in July. The area gets 293 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Annual precipitation totals 45.4 inches. The area receives 23.8 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 39. The city sits at an elevation of 655 feet.
Temperature
31°F Jan (-1°C)74°F Jul (23°C)
Annual Average
53.1°F
2% below US avg
January Average
31°F (-1°C)
July Average
74°F (23°C)
Sunny Days
293 days/yr
Geography
Elevation
655 ft (200 m)
Area
1.0 sq mi (2.7 km²)
Population Density
2,135/sq mi
Coordinates
39.3944°N, 81.2037°W
Timezone
America/New_York
County
Pleasants County County
Nearest Airport
Mid-Ohio Valley Regional (PKB) 13 miles away
Precipitation & Snow
Annual Rainfall45.4"
19% above US avg
Snowfall23.8"
Wettest Month (Jul)4.25"
Driest Month (Feb)2.68"
Air Quality
AQI Median
39.0
Rating
Good
Natural Hazard Risk
Overall Risk
Very Low
Risk Score
20.3 / 100
Social Vulnerability
76.3 / 100
Community Resilience
67.3 / 100
Hazard Breakdown
Tornado
Very Low
Hurricane
Very Low
Earthquake
Very Low
Wildfire
Very Low
Flood
Relatively Low
Hail
Very Low
Strong Wind
Very Low
Heat Wave
Very Low
Winter Weather
Very Low
Lightning
Relatively Low
Ice Storm
Relatively Low
Drought
Very Low
Cold Wave
Very Low
Landslide
Relatively Low
Avalanche
Very Low
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
41 earthquakes (M2.5+) recorded within 150 km since 1990.
Strongest on record: M3.5.
Nov 20, 2013
2 km SW of Buchtel, Ohio
M3.5
86 km
8 km
May 24, 2017
1 km S of McArthur, Ohio
M3.4
111 km
10 km
Apr 4, 2010
14 km SW of Gassaway, West Virginia
M3.4
92 km
0 km
Apr 24, 2009
7 km ENE of Rio Grande, Ohio
M3.4
109 km
8 km
Jun 3, 2017
1 km WNW of Batesville, Ohio
M3.4
59 km
2 km
Mar 31, 2013
West Virginia
M3.4
89 km
8 km
Feb 3, 2025
2 km NNW of Oak Hill, Ohio
M3.1
130 km
26 km
Aug 31, 2011
3 km SE of Lowell, Ohio
M3.1
26 km
5 km
Apr 22, 2025
3 km ESE of Buffalo, Ohio
M3.1
61 km
5 km
Apr 24, 2025
3 km S of Pleasant City, Ohio
M3.1
61 km
6 km
Apr 2, 2017
5 km W of Graysville, Ohio
M3.0
30 km
4 km
Jun 28, 1991
4 km ENE of Pratt, West Virginia
M3.0
130 km
7 km
May 9, 2025
3 km S of Pleasant City, Ohio
M2.9
60 km
5 km
Feb 3, 2025
0 km NE of Reno, Ohio
M2.8
16 km
10 km
Apr 29, 2025
1 km SE of Pleasant City, Ohio
M2.8
62 km
2 km
Jan 10, 2012
14 km WNW of Birch River, West Virginia
M2.8
96 km
0 km
May 6, 2002
3 km SE of Racine, Ohio
M2.8
77 km
5 km
Aug 31, 2011
2 km NNW of Belmont, West Virginia
M2.8
6 km
5 km
Jul 30, 2013
12 km SSW of Glenville, West Virginia
M2.8
67 km
13 km
Jul 20, 2013
6 km SW of Glenville, West Virginia
M2.7
62 km
21 km
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
114 tornadoes (EF0+) recorded within 100 km since 1950.
Strongest on record: EF3. Total: 3 fatalities, 71 injuries.
Date
Rating
Distance
Path
Fatalities
Sep 16, 2010
EF3
57 km
9.1 mi
1
Oct 1, 1986
EF3
38 km
1.0 mi
0
Feb 28, 2024
EF2
47 km
4.1 mi
0
Aug 1, 2022
EF2
91 km
1.8 mi
0
Jul 29, 2021
EF2
90 km
2.7 mi
0
Sep 16, 2010
EF2
90 km
3.3 mi
0
Jul 10, 2003
EF2
42 km
2.5 mi
0
Jun 27, 1998
EF2
48 km
0.3 mi
1
Jan 8, 1998
EF2
27 km
2.0 mi
0
Mar 10, 1986
EF2
84 km
5.0 mi
1
Jul 28, 1981
EF2
9 km
6.2 mi
0
Jun 21, 1981
EF2
75 km
1.0 mi
0
Jun 13, 1981
EF2
95 km
2.3 mi
0
Jun 7, 1978
EF2
84 km
0.8 mi
0
Aug 14, 1973
EF2
96 km
12.5 mi
0
Jul 24, 1971
EF2
42 km
1.0 mi
0
Jul 13, 1971
EF2
83 km
2.0 mi
0
Aug 22, 1970
EF2
87 km
1.0 mi
0
Jun 25, 1968
EF2
79 km
8.5 mi
0
Jun 25, 1968
EF2
91 km
0.1 mi
0
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
4 wildfires (100+ acres) recorded within 100 km.
Largest: LONG RIDGE RX UNIT 37-38 (1,050 acres, 2022).
Year
Name
Acres Burned
Distance
2022
LONG RIDGE RX UNIT 37-38
1,050
81 km
2021
LONG RIDGE RX UNIT 1-12
1,037
85 km
2022
LONG RIDGE RX UNIT 11-19
936
85 km
2022
LONG RIDGE RX UNIT 24
709
81 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
Month
Avg Temperature
Precipitation
Summary
January
31°F (-1°C)
2.8 in
Coldest
February
33°F (0°C)
2.7 in
Driest
March
42°F (6°C)
3.6 in
April
52°F (11°C)
3.4 in
May
61°F (16°C)
3.9 in
June
69°F (21°C)
3.8 in
July
74°F (23°C)
4.3 in
Warmest, Wettest
August
72°F (22°C)
4.0 in
September
65°F (19°C)
3.2 in
October
54°F (12°C)
2.9 in
November
44°F (7°C)
3.3 in
December
34°F (1°C)
3.1 in
St. Marys has a seasonal temperature swing of 44°F / from 31°F in January to 74°F in July. Total annual precipitation is 41.0 inches, with July being the wettest month (4.3") and February the driest (2.7").