Weather & Climate in Rock City, IL

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

Rock City experiences four distinct seasons with an average annual temperature of 49°F (10°C). Winters average 22°F in January while summers reach 74°F in July. The area gets 260 sunny days per year, above the national average. Annual precipitation totals 37.2 inches. The area receives 37.1 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 905 feet.

Temperature

22°F Jan (-6°C) 74°F Jul (23°C)

Annual Average	49.4°F
	9% below US avg
January Average	22°F (-6°C)
July Average	74°F (23°C)
Sunny Days	260 days/yr

Geography

Elevation	905 ft (276 m)
Area	0.1 sq mi (0.2 km²)
Population Density	2,700/sq mi
Coordinates	42.4130°N, 89.4710°W
Timezone	America/Chicago
County	Stephenson County County
Nearest Airport	Chicago/Rockford International (RFD) 24 miles away

Precipitation & Snow

Annual Rainfall 37.2"

2% below US avg

Snowfall 37.1"

Wettest Month (Jun) 4.25"

Driest Month (Feb) 1.18"

Air Quality

AQI Median	43.0
Rating	Good

Natural Hazard Risk

Overall Risk	Relatively Low
Risk Score	73.9 / 100
Social Vulnerability	56.7 / 100
Community Resilience	68.6 / 100

Hazard Breakdown

Tornado	Relatively Moderate
Hurricane	Very Low
Earthquake	Very Low
Wildfire	Very Low
Flood	Relatively Moderate
Hail	Relatively Moderate
Strong Wind	Relatively High
Heat Wave	Relatively Low
Winter Weather	Relatively Low
Lightning	Relatively Low
Ice Storm	Relatively Moderate
Drought	Relatively Moderate
Cold Wave	Relatively Moderate
Landslide	Very Low

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

Earthquake History

6 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M4.2.

Jun 28, 2004	12 km NW of Dayton, Illinois	M4.2	116 km	10 km
Feb 10, 2010	2 km NW of Lily Lake, Illinois	M3.8	94 km	10 km
Sep 2, 1999	8 km W of Amboy, Illinois	M3.5	77 km	5 km
Jul 15, 2024	2 km WNW of Somonauk, Illinois	M3.1	106 km	10 km
Mar 25, 2015	3 km WNW of Lake in the Hills, Illinois	M2.9	94 km	6 km
Jun 10, 2013	4 km NNE of Virgil, Illinois	M2.6	92 km	5 km

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

Tornado History

561 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 52 fatalities, 1,046 injuries.

Date	Rating	Distance	Path	Fatalities
Jun 7, 1984	EF5	75 km	36.0 mi	9
Apr 9, 2015	EF4	64 km	30.1 mi	2
Jul 3, 1983	EF4	82 km	0.5 mi	0
Mar 29, 1981	EF4	91 km	5.1 mi	0
Apr 21, 1967	EF4	50 km	25.5 mi	24
Apr 11, 1965	EF4	92 km	9.1 mi	6
Jun 16, 2014	EF3	66 km	1.0 mi	0
Jan 7, 2008	EF3	53 km	13.2 mi	0
Jan 7, 2008	EF3	95 km	10.8 mi	0
Aug 18, 2005	EF3	57 km	18.6 mi	1
Jun 17, 1992	EF3	52 km	16.0 mi	0
May 8, 1988	EF3	65 km	16.0 mi	0
Jun 5, 1980	EF3	98 km	10.7 mi	0
Aug 5, 1979	EF3	45 km	5.7 mi	0
Jun 4, 1975	EF3	93 km	2.3 mi	0
Jun 20, 1974	EF3	82 km	10.6 mi	1
Sep 9, 1970	EF3	99 km	4.7 mi	0
Aug 2, 1967	EF3	80 km	0.1 mi	2
Apr 16, 1967	EF3	40 km	27.8 mi	0
Jan 24, 1967	EF3	22 km	24.9 mi	0

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

Wildfire History

2 wildfires (100+ acres) recorded within 100 km. Largest: RX-HWY Y - SOUTH (553 acres, 2024).

Year	Name	Acres Burned	Distance
2024	RX-HWY Y - SOUTH	553	85 km
2009	COLD SPRINGS	552	32 km

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

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	22°F (-6°C)	1.2 in	Coldest
February	22°F (-5°C)	1.2 in	Driest
March	34°F (1°C)	2.3 in
April	47°F (8°C)	3.3 in
May	59°F (15°C)	3.7 in
June	68°F (20°C)	4.3 in	Wettest
July	74°F (23°C)	3.8 in	Warmest
August	70°F (21°C)	4.1 in
September	62°F (17°C)	3.8 in
October	50°F (10°C)	2.6 in
November	36°F (2°C)	2.4 in
December	23°F (-5°C)	1.9 in

Rock City has a seasonal temperature swing of 52°F / from 22°F in January to 74°F in July. Total annual precipitation is 34.5 inches, with June being the wettest month (4.3") and February the driest (1.2").

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