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Algonquin, IL
Full City Profile · Illinois · McHenry County County
3.8
/5.0
B+
Good
29,904
Population
2,389/sq mi density
$131,753
Median Income
$53,698 per capita
$324,000
Home Value
$398,699 Zillow
$1,800
Median Rent
25.5% income on rent
49°F
Avg Temperature
260 sunny days/yr
74
Violent Crime/100K
977 property/100K
B+
Overall
3.8 / 5.0
Good overall score based on economy, affordability, safety and education
A+
Economy
4.8 / 5.0
$131,753 median income, 3.2% unemployment
A+
Affordability
5.0 / 5.0
$324,000 home value, $1,800/mo rent
F
Safety
1.0 / 5.0
74 violent crimes/100K
A
Education
4.5 / 5.0
43.6% bachelor's degree or higher
Algonquin experiences four distinct seasons with an average annual temperature of 49°F (9°C). Winters average 22°F in January while summers reach 74°F in July. The area gets 260 sunny days per year. Annual precipitation totals 39.9 inches. The area receives 32.1 inches of snow annually. Air quality is rated Good with a median AQI of 43.
Temperature
22°F Jan (-6°C)
74°F Jul (23°C)
| Annual Average | 49.0°F |
| 9% below US avg | |
| January Average | 22°F (-6°C) |
| July Average | 74°F (23°C) |
| Sunny Days | 260 days/yr |
Geography
| Elevation | 908 ft (277 m) |
| Area | 4.8 sq mi (12.4 km²) |
| Population Density | 2,389/sq mi |
| Coordinates | 42.1595°N, 88.3219°W |
| Timezone | America/Chicago |
| County | McHenry County County |
| Nearest Airport | Chicago O'Hare International (ORD) 25 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 | 130 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 22°F (-6°C) | 1.6 in | Coldest |
| February | 26°F (-4°C) | 1.3 in | Driest |
| March | 36°F (2°C) | 2.5 in | |
| April | 48°F (9°C) | 3.7 in | |
| May | 59°F (15°C) | 3.5 in | |
| June | 68°F (20°C) | 4.2 in | Wettest |
| July | 74°F (23°C) | 4.0 in | Warmest |
| August | 71°F (22°C) | 4.1 in | |
| September | 63°F (17°C) | 3.9 in | |
| October | 52°F (11°C) | 2.5 in | |
| November | 39°F (4°C) | 2.9 in | |
| December | 26°F (-3°C) | 2.1 in |
Algonquin has a seasonal temperature swing of 52°F / from 22°F in January to 74°F in July. Total annual precipitation is 36.2 inches, with June being the wettest month (4.2") and February the driest (1.3").