Weather & Climate in Janesville, CA

Temperature, precipitation, air quality, natural hazards, and monthly weather data.

Janesville experiences four distinct seasons with an average annual temperature of 50°F (10°C). Winters average 33°F in January while summers reach 71°F in July. The area gets 316 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 13.0 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 4,103 feet.

Temperature

33°F Jan (0°C) 71°F Jul (21°C)

Annual Average	50.2°F
	7% below US avg
January Average	33°F (0°C)
July Average	71°F (21°C)
Sunny Days	316 days/yr

Geography

Elevation	4,103 ft (1,251 m)
Area	13.2 sq mi (34.2 km²)
Population Density	72/sq mi
Coordinates	40.3011°N, 120.4903°W
Timezone	America/Los_Angeles
County	Lassen County County
Nearest Airport	Reno/Tahoe International (RNO) 67 miles away

Precipitation & Snow

Annual Rainfall 13.0"

66% below US avg

Wettest Month (Jan) 2.68"

Driest Month (Jul) 0.31"

Air Quality

AQI Median	48.0
Rating	Good

Natural Hazard Risk

Overall Risk	Relatively Low
Risk Score	73.1 / 100
Social Vulnerability	69.3 / 100
Community Resilience	56.6 / 100

Hazard Breakdown

Tornado	Very Low
Earthquake	Relatively Low
Wildfire	Relatively Moderate
Flood	Relatively Moderate
Hail	Very Low
Strong Wind	Very Low
Heat Wave	Very Low
Winter Weather	Relatively Moderate
Lightning	Relatively Low
Drought	Relatively Moderate
Cold Wave	Very Low
Landslide	Very Low
Volcano	Relatively Low
Avalanche	Very Low

Source: FEMA National Risk Index v1.20 (Dec 2025)

Earthquake History

1,646 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M5.7.

May 24, 2013	2 km NNE of Canyondam, California	M5.7	50 km	8 km
May 11, 2023	Lake Almanor Earthquake	M5.5	54 km	6 km
Aug 10, 2001	3 km N of Blairsden, California	M5.2	56 km	5 km
May 12, 2023	4km NW of Canyondam, CA	M5.2	53 km	6 km
Apr 26, 2008	1 km NW of Mogul, Nevada	M5.1	99 km	3 km
Sep 8, 2023	12 km NE of Burney, CA	M5.0	116 km	16 km
May 24, 2013	1km NNW of Canyondam, CA	M4.9	52 km	4 km
Oct 30, 1998	4 km N of Tahoe Vista, California	M4.8	119 km	1 km
Feb 10, 1993	28 km SW of Empire, Nevada	M4.8	76 km	5 km
Apr 26, 2008	0 km N of Mogul, Nevada	M4.8	99 km	3 km
Jun 26, 2005	8 km NNW of Tahoe Vista, California	M4.8	116 km	-2 km
May 7, 2021	19km NW of Truckee, CA	M4.7	95 km	10 km
Mar 21, 2020	5 km NE of Indian Hills, Nevada	M4.5	147 km	8 km
Nov 15, 1995	9 km SW of Cold Springs, Nevada	M4.5	84 km	-1 km
Aug 4, 2016	5 km WNW of Patton Village, California	M4.5	29 km	7 km
May 10, 2005	10 km NW of Burney, California	M4.4	129 km	17 km
Apr 5, 2024	6 km NW of Belden, CA	M4.4	75 km	8 km
Mar 27, 1997	14km SW of Manton, CA	M4.4	126 km	8 km
Dec 20, 2000	12 km NNW of Burney, California	M4.4	127 km	17 km
Jun 14, 1991	8 km SW of Hat Creek, California	M4.4	108 km	11 km

Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.

Tornado History

9 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF1. Total: 1 injury.

Date	Rating	Distance	Path	Fatalities
Aug 15, 2020	EF1	71 km	0.1 mi	0
Aug 14, 2020	EF1	71 km	0.4 mi	0
Nov 3, 1973	EF1	72 km	25.9 mi	0
Jul 16, 1973	EF1	99 km	1.0 mi	0
Jul 20, 2015	EF0	57 km	3.2 mi	0
Jul 24, 2004	EF0	94 km	0.1 mi	0
Aug 2, 2003	EF0	96 km	0.1 mi	0
Jul 30, 1998	EF0	92 km	2.0 mi	0
Apr 23, 1964	EF0	90 km	1.0 mi	0

Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).

Nearby Volcanoes

4 volcanoes within 200 km. Closest: Lassen Volcanic Center (89 km).

Name	Type	Elevation	Last Eruption	Distance
Lassen Volcanic Center	Stratovolcano	3,187 m (10,456 ft)	1917	89 km
Soda Lakes	Maar(s)	1,251 m (4,104 ft)	Unknown	163 km
Medicine Lake	Shield	2,412 m (7,913 ft)	1060	171 km
Shasta	Stratovolcano	4,317 m (14,163 ft)	1250	189 km

Source: Smithsonian Institution Global Volcanism Program (GVP).

Wildfire History

20 wildfires (100+ acres) recorded within 100 km. Largest: DIXIE (979,795 acres, 2021).

Year	Name	Acres Burned	Distance
2021	DIXIE	979,795	32 km
2020	NORTH COMPLEX	316,556	84 km
2012	RUSH	306,811	48 km
2021	SUGAR	108,368	46 km
2017	TOHAKUM 2	92,711	95 km
2020	W-5 COLD SPRINGS	84,024	96 km
2017	LONG VALLEY	80,456	59 km
2012	CHIPS	79,978	64 km
2001	OBSERVATION	67,432	55 km
2007	MOONLIGHT	65,718	23 km
2019	WALKER	58,747	25 km
2008	BTU LIGHTNING COMPLEX (LONG BRANCH-JACK)	52,091	95 km
2000	STORRIE	49,588	74 km
1994	COTTONWOOD	47,912	82 km
1999	FISH COMPLEX (FISH SPRINGS)	47,030	63 km
2020	LOYALTON	45,484	74 km
2014	BALD	39,770	94 km
1987	CLARK	39,194	27 km
2016	TULE	35,341	78 km
1999	MHRD COMPLEX (BUCKS)	34,459	84 km

Source: NIFC/IRWIN Wildfire Records (100+ acres).

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	33°F (0°C)	2.7 in	Wettest
February	35°F (2°C)	2.2 in
March	41°F (5°C)	1.9 in
April	46°F (8°C)	0.8 in
May	53°F (12°C)	1.0 in
June	61°F (16°C)	0.6 in
July	71°F (21°C)	0.3 in	Warmest, Driest
August	67°F (20°C)	0.3 in
September	60°F (16°C)	0.6 in
October	50°F (10°C)	1.2 in
November	39°F (4°C)	2.2 in
December	32°F (0°C)	2.3 in	Coldest

Janesville has a seasonal temperature swing of 39°F / from 32°F in December to 71°F in July. Total annual precipitation is 16.1 inches, with January being the wettest month (2.7") and July the driest (0.3").

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