Grayslake, IL
Full City Profile · Illinois · McHenry County County
3.9
/5.0
B+
Good
20,707
Population
1,895/sq mi density
$113,697
Median Income
$53,833 per capita
$293,900
Home Value
$373,951 Zillow
$1,434
Median Rent
26.5% income on rent
48°F
Avg Temperature
70
Violent Crime/100K
645 property/100K
B+
Overall
3.9 / 5.0
Good overall score based on economy, affordability, safety and education
A
Economy
4.4 / 5.0
$113,697 median income, 5.7% unemployment
A+
Affordability
5.0 / 5.0
$293,900 home value, $1,434/mo rent
F
Safety
1.0 / 5.0
70 violent crimes/100K
A+
Education
5.0 / 5.0
59.1% bachelor's degree or higher
Grayslake experiences four distinct seasons with an average annual temperature of 48°F (9°C). Winters average 23°F in January while summers reach 72°F in July. Annual precipitation totals 36.4 inches. The area receives 43.1 inches of snow annually. Air quality is rated Good with a median AQI of 43.
Temperature
23°F Jan (-5°C)
72°F Jul (22°C)
| Annual Average | 48.3°F |
| 11% below US avg | |
| January Average | 23°F (-5°C) |
| July Average | 72°F (22°C) |
Geography
| Elevation | 779 ft (237 m) |
| Area | 10.9 sq mi (28.3 km²) |
| Population Density | 1,895/sq mi |
| Coordinates | 42.3408°N, 88.0336°W |
| Timezone | America/Chicago |
| County | McHenry County County |
| Nearest Airport | Kenosha Regional (ENW) 18 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
| Good Days % | 66.9% |
| Unhealthy Days | 1 |
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 | 119 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 23°F (-5°C) | 2.2 in | Coldest |
| February | 26°F (-3°C) | 1.9 in | |
| March | 36°F (2°C) | 2.4 in | |
| April | 46°F (8°C) | 3.7 in | |
| May | 56°F (14°C) | 4.1 in | |
| June | 66°F (19°C) | 4.1 in | Wettest |
| July | 72°F (22°C) | 3.9 in | Warmest |
| August | 71°F (21°C) | 3.4 in | |
| September | 63°F (17°C) | 3.3 in | |
| October | 52°F (11°C) | 3.1 in | |
| November | 40°F (4°C) | 2.4 in | |
| December | 29°F (-2°C) | 1.9 in | Driest |
Grayslake has a seasonal temperature swing of 48°F / from 23°F in January to 72°F in July. Total annual precipitation is 36.4 inches, with June being the wettest month (4.1") and December the driest (1.9").