Frankfort, IL
Full City Profile · Illinois · Will County County
3.9
/5.0
B+
Good
20,417
Population
1,307/sq mi density
$153,714
Median Income
$59,421 per capita
$461,600
Home Value
$503,107 Zillow
$2,175
Median Rent
28.4% income on rent
50°F
Avg Temperature
33
Violent Crime/100K
668 property/100K
B+
Overall
3.9 / 5.0
Good overall score based on economy, affordability, safety and education
A+
Economy
4.8 / 5.0
$153,714 median income, 3.6% unemployment
A+
Affordability
5.0 / 5.0
$461,600 home value, $2,175/mo rent
F
Safety
1.0 / 5.0
33 violent crimes/100K
A+
Education
5.0 / 5.0
59.2% bachelor's degree or higher
Frankfort experiences four distinct seasons with an average annual temperature of 50°F (10°C). Winters average 23°F in January while summers reach 74°F in July. Annual precipitation totals 41.3 inches. The area receives 28.2 inches of snow annually. Air quality is rated Good with a median AQI of 44.
Temperature
23°F Jan (-5°C)
74°F Jul (23°C)
| Annual Average | 49.8°F |
| 8% below US avg | |
| January Average | 23°F (-5°C) |
| July Average | 74°F (23°C) |
Geography
| Elevation | 719 ft (219 m) |
| Area | 15.6 sq mi (40.5 km²) |
| Population Density | 1,307/sq mi |
| Coordinates | 41.5070°N, 87.8710°W |
| Timezone | America/Chicago |
| County | Will County County |
| Nearest Airport | Joliet Regional (JOT) 16 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 44.0 |
| Rating | Good |
| Good Days % | 67.1% |
| Unhealthy Days | 0 |
Air Pollutants (EPA 2023)
| Ozone (O₃) | 0.0479 ppm |
| PM2.5 (Fine Particles) | 9.5 μg/m³ |
Natural Hazard Risk
| Overall Risk | Relatively High |
| Risk Score | 97.3 / 100 |
| Social Vulnerability | 13.4 / 100 |
| Community Resilience | 92.4 / 100 |
Hazard Breakdown
| Tornado | Very High |
| Hurricane | Very Low |
| Earthquake | Relatively Moderate |
| Wildfire | Very Low |
| Flood | Relatively High |
| Hail | Relatively Low |
| Strong Wind | Relatively Low |
| Heat Wave | Relatively Moderate |
| Winter Weather | Relatively High |
| Lightning | Relatively High |
| Ice Storm | Relatively Moderate |
| Drought | Relatively Low |
| Cold Wave | Very 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 | 85 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 23°F (-5°C) | 2.3 in | Coldest |
| February | 27°F (-3°C) | 2.2 in | Driest |
| March | 37°F (3°C) | 2.6 in | |
| April | 49°F (9°C) | 4.0 in | |
| May | 60°F (16°C) | 4.6 in | |
| June | 70°F (21°C) | 4.7 in | Wettest |
| July | 74°F (23°C) | 4.7 in | Warmest |
| August | 72°F (22°C) | 4.2 in | |
| September | 65°F (18°C) | 3.5 in | |
| October | 53°F (12°C) | 3.5 in | |
| November | 40°F (4°C) | 2.7 in | |
| December | 29°F (-2°C) | 2.4 in |
Frankfort has a seasonal temperature swing of 51°F / from 23°F in January to 74°F in July. Total annual precipitation is 41.3 inches, with June being the wettest month (4.7") and February the driest (2.2").