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Crystal Lake, IL
Full City Profile · Illinois · McHenry County County
3.8
/5.0
B+
Good
40,436
Population
2,129/sq mi density
$105,428
Median Income
$46,199 per capita
$287,400
Home Value
$367,174 Zillow
$1,431
Median Rent
29.8% income on rent
49°F
Avg Temperature
260 sunny days/yr
113
Violent Crime/100K
1,229 property/100K
B+
Overall
3.8 / 5.0
Good overall score based on economy, affordability, safety and education
A+
Economy
4.8 / 5.0
$105,428 median income, 3.2% unemployment
A+
Affordability
5.0 / 5.0
$287,400 home value, $1,431/mo rent
F
Safety
1.0 / 5.0
113 violent crimes/100K
A
Education
4.4 / 5.0
42.0% bachelor's degree or higher
Crystal Lake experiences four distinct seasons with an average annual temperature of 49°F (9°C). Winters average 23°F in January while summers reach 73°F in July. The area gets 260 sunny days per year. Annual precipitation totals 39.4 inches. The area receives 35.1 inches of snow annually. Air quality is rated Good with a median AQI of 43.
Temperature
23°F Jan (-5°C)
73°F Jul (23°C)
| Annual Average | 49.2°F |
| 9% below US avg | |
| January Average | 23°F (-5°C) |
| July Average | 73°F (23°C) |
| Sunny Days | 260 days/yr |
Geography
| Elevation | 902 ft (275 m) |
| Area | 19.0 sq mi (49.1 km²) |
| Population Density | 2,129/sq mi |
| Coordinates | 42.2332°N, 88.3344°W |
| Timezone | America/Chicago |
| County | McHenry County County |
| Nearest Airport | Chicago O'Hare International (ORD) 28 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Air Pollutants (EPA 2023)
| Ozone (O₃) | 0.0484 ppm |
| PM2.5 (Fine Particles) | 9.1 μg/m³ |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 90.8 / 100 |
| Social Vulnerability | 10.6 / 100 |
| Community Resilience | 84.0 / 100 |
Hazard Breakdown
| Tornado | Relatively High |
| Hurricane | Very Low |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Relatively Moderate |
| Hail | Relatively Moderate |
| Strong Wind | Relatively High |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Moderate |
| Lightning | Relatively Moderate |
| Ice Storm | Relatively Low |
| Drought | Relatively Low |
| Cold Wave | Relatively High |
| Landslide | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Tsunami History
1 tsunami recorded within 500 km. Highest wave on record: 3.0 m (10 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1954 | MICHIGAN CITY, IN (LAKE MICHIGAN) | Avalanche | 3.0 m | 7 | 134 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 23°F (-5°C) | 1.5 in | Coldest |
| February | 24°F (-4°C) | 1.2 in | Driest |
| March | 35°F (2°C) | 2.5 in | |
| April | 47°F (8°C) | 3.7 in | |
| May | 58°F (15°C) | 3.6 in | |
| June | 68°F (20°C) | 4.2 in | Wettest |
| July | 73°F (23°C) | 4.1 in | Warmest |
| August | 70°F (21°C) | 4.2 in | |
| September | 62°F (17°C) | 3.9 in | |
| October | 51°F (10°C) | 2.6 in | |
| November | 38°F (3°C) | 2.8 in | |
| December | 25°F (-4°C) | 2.1 in |
Crystal Lake has a seasonal temperature swing of 50°F / from 23°F in January to 73°F in July. Total annual precipitation is 36.3 inches, with June being the wettest month (4.2") and February the driest (1.2").