Temperature, precipitation, air quality, natural hazards, and monthly weather data.
McSwain enjoys a temperate climate with an average annual temperature of 62°F (16°C). Winters average 46°F in January while summers reach 78°F in July. The area gets 330 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 12.5 inches (drier than the 38-inch national average). Air quality is rated Good with a median AQI of 48. The city sits at an elevation of 143 feet.
Temperature
46°F Jan (8°C)78°F Jul (26°C)
Annual Average
61.6°F
14% above US avg
January Average
46°F (8°C)
July Average
78°F (26°C)
Sunny Days
330 days/yr
Geography
Elevation
143 ft (44 m)
Area
6.0 sq mi (15.6 km²)
Population Density
921/sq mi
Coordinates
37.3145°N, 120.5868°W
Timezone
America/Los_Angeles
County
Merced County County
Nearest Airport
Merced Yosemite Regional (MCE) 5 miles away
Precipitation & Snow
Annual Rainfall12.5"
67% below US avg
Snowfall0.0"
Wettest Month (Jan)2.17"
Driest Month (Jul)0.04"
Air Quality
AQI Median
48.0
Rating
Good
Natural Hazard Risk
Overall Risk
Relatively High
Risk Score
96.9 / 100
Social Vulnerability
61.7 / 100
Community Resilience
7.3 / 100
Hazard Breakdown
Tornado
Relatively Low
Earthquake
Relatively High
Wildfire
Relatively Moderate
Flood
Relatively High
Hail
Relatively Low
Strong Wind
Relatively Low
Heat Wave
Relatively High
Winter Weather
Very Low
Lightning
Relatively High
Drought
Very High
Cold Wave
No Rating
Landslide
Very Low
Volcano
Very Low
Avalanche
Very Low
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
4,830 earthquakes (M2.5+) recorded within 150 km since 1990.
Strongest on record: M5.4.
Apr 18, 1990
5 km NNW of Aromas, California
M5.4
104 km
5 km
Oct 21, 2012
24 km NE of San Lucas, California
M5.3
114 km
9 km
Apr 18, 1990
4 km E of Interlaken, California
M5.1
105 km
7 km
Aug 12, 1998
10 km SW of Ridgemark, California
M5.1
100 km
9 km
Jan 16, 1993
9 km E of Gilroy, California
M4.9
84 km
7 km
Apr 23, 1995
22 km NNE of Soledad, California
M4.9
96 km
7 km
May 14, 2002
5 km SSW of Gilroy, California
M4.9
98 km
7 km
Apr 19, 1996
2 km E of Aromas, California
M4.9
103 km
5 km
Apr 18, 1990
4 km NNW of Aromas, California
M4.9
104 km
6 km
Nov 30, 1997
2 km ESE of Mammoth Lakes, California
M4.9
149 km
5 km
Sep 30, 2004
13 km NW of Parkfield, California
M4.9
148 km
10 km
Nov 22, 1997
3 km ESE of Mammoth Lakes, California
M4.9
150 km
5 km
Apr 18, 1990
4 km N of Aromas, California
M4.7
103 km
4 km
May 21, 1996
8 km ESE of East Foothills, California
M4.7
101 km
8 km
Aug 11, 1993
14 km ESE of Alum Rock, California
M4.7
97 km
9 km
Aug 27, 2011
21 km NE of Soledad, California
M4.6
97 km
8 km
Mar 24, 1991
1 km NNE of Interlaken, California
M4.6
108 km
15 km
Sep 19, 2023
15 km SW of Westley, CA
M4.5
64 km
4 km
Nov 22, 1997
California-Nevada border region
M4.5
149 km
6 km
Jan 12, 2011
9 km SSE of San Juan Bautista, California
M4.5
101 km
8 km
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
79 tornadoes (EF0+) recorded within 100 km since 1950.
Strongest on record: EF2. Total: 3 injuries.
Date
Rating
Distance
Path
Fatalities
Mar 11, 1985
EF2
89 km
0.5 mi
0
Mar 22, 1962
EF2
90 km
0.5 mi
0
Apr 27, 1953
EF2
52 km
0.1 mi
0
Mar 11, 2023
EF1
69 km
0.8 mi
0
Jan 10, 2023
EF1
87 km
0.4 mi
0
Nov 15, 2015
EF1
31 km
3.0 mi
0
Apr 14, 2006
EF1
52 km
0.5 mi
0
Dec 16, 2002
EF1
6 km
1.3 mi
0
May 20, 2002
EF1
60 km
2.7 mi
0
Feb 14, 1998
EF1
50 km
3.0 mi
0
Dec 12, 1996
EF1
56 km
0.6 mi
0
Nov 22, 1996
EF1
12 km
0.2 mi
0
Jan 14, 1995
EF1
35 km
1.0 mi
0
Feb 19, 1980
EF1
98 km
1.7 mi
0
Mar 4, 1978
EF1
41 km
2.5 mi
0
Mar 4, 1978
EF1
26 km
1.0 mi
0
Mar 1, 1978
EF1
50 km
1.5 mi
0
May 31, 1967
EF1
96 km
0.1 mi
0
Apr 22, 1967
EF1
28 km
1.0 mi
0
Apr 22, 1967
EF1
69 km
0.1 mi
0
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Tsunami History
4 tsunamis recorded within 500 km.
Highest wave on record: 4.5 m (15 ft).
Year
Location
Cause
Max Wave
Deaths
Distance
1868
N. CALIFORNIA
Eruption + Earthquake
4.5 m
30
140 km
1989
N. CALIFORNIA
Earthquake
1.0 m
62
119 km
1901
MONTEREY BAY, N. CALIFORNIA
Eruption + Earthquake
—
—
146 km
1865
N. CALIFORNIA
Eruption + Earthquake
—
—
117 km
Source: NOAA/NCEI Historical Tsunami Database.
Nearby Volcanoes
3 volcanoes within 200 km.
Closest: Mammoth Mountain (142 km).
Name
Type
Elevation
Last Eruption
Distance
Mammoth Mountain
Lava dome(s)
3,369 m (11,053 ft)
1260
142 km
Mono-Inyo Craters
Lava dome(s)
2,796 m (9,173 ft)
1380
148 km
Mono Lake Volcanic Field
Pyroclastic cone(s)
2,121 m (6,959 ft)
1790
157 km
Source: Smithsonian Institution Global Volcanism Program (GVP).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km.
Largest: SCU LIGHTNING COMPLEX (405,787 acres, 2020).
Year
Name
Acres Burned
Distance
2020
SCU LIGHTNING COMPLEX
405,787
83 km
2013
RIM
257,084
86 km
2018
FERGUSON
97,307
78 km
2017
DETWILER
83,297
49 km
1996
ACKERSON COMPLEX (ACKERSON)
58,161
95 km
1987
PAPER
49,296
78 km
1987
LARSON
49,250
74 km
2007
LICK
47,424
75 km
1987
HAMM
39,333
71 km
2006
CANYON
36,851
67 km
2008
TELEGRAPH
33,479
60 km
2022
OAK
19,408
69 km
1992
GULCH
18,019
97 km
1990
A-ROCK
17,706
82 km
1996
ROGGE
17,559
77 km
2003
ANNIE
17,383
59 km
1996
MERCY
16,993
54 km
2024
CORRAL
16,138
85 km
1996
PANOCHE II
14,760
82 km
2017
RAILROAD
12,765
87 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
Month
Avg Temperature
Precipitation
Summary
January
46°F (8°C)
2.2 in
Wettest
February
50°F (10°C)
2.2 in
March
55°F (13°C)
1.9 in
April
60°F (16°C)
0.8 in
May
67°F (19°C)
0.3 in
June
73°F (23°C)
0.1 in
July
78°F (26°C)
0.0 in
Warmest, Driest
August
75°F (24°C)
0.0 in
September
72°F (22°C)
0.2 in
October
64°F (18°C)
0.7 in
November
53°F (12°C)
1.5 in
December
44°F (7°C)
1.5 in
Coldest
McSwain has a seasonal temperature swing of 34°F / from 44°F in December to 78°F in July. Total annual precipitation is 11.6 inches, with January being the wettest month (2.2") and July the driest (0.0").