Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Calpella enjoys a temperate climate with an average annual temperature of 59°F (15°C). Winters average 47°F in January while summers reach 73°F in July. The area gets 302 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 38.9 inches. Air quality is rated Good with a median AQI of 48. The city sits at an elevation of 822 feet.
Temperature
47°F Jan (8°C)73°F Jul (23°C)
Annual Average
58.9°F
9% above US avg
January Average
47°F (8°C)
July Average
73°F (23°C)
Sunny Days
302 days/yr
Geography
Elevation
822 ft (251 m)
Area
2.6 sq mi (6.6 km²)
Population Density
218/sq mi
Coordinates
39.2337°N, 123.1938°W
Timezone
America/Los_Angeles
County
Mendocino County County
Nearest Airport
Chico Regional (CIC) 79 miles away
Precipitation & Snow
Annual Rainfall38.9"
2% above US avg
Snowfall0.0"
Wettest Month (Jan)9.02"
Driest Month (Jul)0.08"
Air Quality
AQI Median
48.0
Rating
Good
Natural Hazard Risk
Overall Risk
Relatively High
Risk Score
94.3 / 100
Social Vulnerability
76.8 / 100
Community Resilience
39.0 / 100
Hazard Breakdown
Tornado
Very Low
Earthquake
Relatively High
Wildfire
Relatively High
Flood
Relatively High
Hail
Very Low
Strong Wind
Very Low
Heat Wave
Relatively Low
Winter Weather
Very Low
Lightning
Relatively Low
Drought
Relatively High
Cold Wave
No Rating
Landslide
Relatively High
Coastal Flood
Relatively Low
Tsunami
Very Low
Volcano
Very Low
Avalanche
Very Low
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
3,784 earthquakes (M2.5+) recorded within 150 km since 1990.
Strongest on record: M6.0.
Aug 24, 2014
The 2014 South Napa, California Earthquake
M6.0
137 km
11 km
Aug 17, 1991
30 km SSW of Scotia, California
M6.0
147 km
8 km
Jun 23, 2019
6km SSW of Petrolia, CA
M5.6
149 km
9 km
Jan 16, 1990
30 km NW of Shelter Cove, California
M5.4
147 km
4 km
Jan 1, 2023
15km SE of Rio Dell, CA
M5.4
147 km
31 km
Mar 8, 1992
27 km NW of Shelter Cove, California
M5.3
144 km
9 km
Aug 10, 2016
20 km NNE of Upper Lake, California
M5.1
35 km
14 km
Sep 3, 2000
5 km WSW of Yountville, California
M4.9
117 km
9 km
Sep 4, 1995
13 km SW of Middletown, California
M4.8
73 km
7 km
Apr 18, 2007
15 km N of Potter Valley, California
M4.8
27 km
5 km
May 12, 2006
7 km W of Cobb, California
M4.7
57 km
4 km
Jan 19, 2008
31 km NW of Rancho Tehama Reserve, California
M4.7
113 km
2 km
Jan 2, 2025
4 km NW of Cobb, CA
M4.7
57 km
1 km
Jan 11, 2000
6 km N of Geyserville, California
M4.6
57 km
6 km
Feb 18, 2004
4 km WNW of Cobb, California
M4.6
58 km
3 km
Jan 12, 2014
8 km W of Cobb, California
M4.5
57 km
2 km
Sep 25, 2012
3 km N of Talmage, California
M4.5
8 km
11 km
Aug 3, 2006
5 km W of Glen Ellen, California
M4.5
110 km
9 km
Jan 19, 2008
34 km WNW of Rancho Tehama Reserve, California
M4.5
110 km
10 km
Aug 28, 2016
8 km ESE of Mad River, California
M4.5
135 km
36 km
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
24 tornadoes (EF0+) recorded within 100 km since 1950.
Strongest on record: EF1.
Date
Rating
Distance
Path
Fatalities
Mar 26, 2014
EF1
98 km
0.6 mi
0
May 25, 2011
EF1
91 km
26.4 mi
0
May 25, 2011
EF1
99 km
21.7 mi
0
Mar 18, 2011
EF1
97 km
0.1 mi
0
Jan 27, 2005
EF1
69 km
0.5 mi
0
Dec 5, 1998
EF1
97 km
1.5 mi
0
Dec 5, 1998
EF1
58 km
1.7 mi
0
Feb 22, 1996
EF1
86 km
1.0 mi
0
Apr 17, 1993
EF1
97 km
0.5 mi
0
Dec 2, 1992
EF1
98 km
1.0 mi
0
Dec 2, 1992
EF1
83 km
3.0 mi
0
Dec 2, 1992
EF1
96 km
7.5 mi
0
Feb 27, 1983
EF1
97 km
0.8 mi
0
Nov 10, 1964
EF1
85 km
1.0 mi
0
Feb 17, 1959
EF1
80 km
0.5 mi
0
Feb 19, 2013
EF0
81 km
0.3 mi
0
Mar 23, 2011
EF0
89 km
1.1 mi
0
Mar 21, 2011
EF0
83 km
0.3 mi
0
Mar 8, 2010
EF0
78 km
0.3 mi
0
Jun 6, 2005
EF0
96 km
0.1 mi
0
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Nearby Volcanoes
1 volcano within 200 km.
Closest: Clear Lake (47 km).
Name
Type
Elevation
Last Eruption
Distance
Clear Lake
Volcanic field
1,439 m (4,721 ft)
Unknown
47 km
Source: Smithsonian Institution Global Volcanism Program (GVP).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km.
Largest: AUGUST COMPLEX (1,068,802 acres, 2020).
Year
Name
Acres Burned
Distance
2020
AUGUST COMPLEX
1,068,802
80 km
2018
RANCH
427,048
36 km
2015
ROCKY
96,125
74 km
2008
YOLLA BOLLY COMPLEX (IRON)
94,888
98 km
1996
FORK
83,209
39 km
2019
KINCADE
77,780
72 km
2015
VALLEY
77,507
71 km
2020
GLASS
68,020
94 km
2020
WALLBRIDGE
55,194
70 km
1987
MENDENHALL
54,162
37 km
2018
RIVER
48,920
25 km
2012
NORTH PASS
43,689
75 km
2004
RUMSEY
39,335
96 km
1999
SIXTEEN
37,162
89 km
2017
TUBBS
36,981
86 km
2017
REDWOOD VALLEY INCIDENT
36,545
12 km
2012
MILL
29,924
50 km
2001
TROUGH
25,270
46 km
2017
POCKET
18,691
58 km
2012
SIXTEEN COMPLEX
18,191
81 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
Month
Avg Temperature
Precipitation
Summary
January
47°F (8°C)
9.0 in
Wettest
February
48°F (9°C)
6.9 in
March
49°F (10°C)
6.3 in
April
52°F (11°C)
2.6 in
May
58°F (14°C)
1.0 in
June
64°F (18°C)
0.2 in
July
73°F (23°C)
0.1 in
Warmest, Driest
August
69°F (21°C)
0.2 in
September
66°F (19°C)
0.8 in
October
59°F (15°C)
2.5 in
November
50°F (10°C)
6.7 in
December
45°F (7°C)
7.6 in
Coldest
Calpella has a seasonal temperature swing of 28°F / from 45°F in December to 73°F in July. Total annual precipitation is 44.0 inches, with January being the wettest month (9.0") and July the driest (0.1").