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Grafton, IL
Full City Profile · Illinois · St. Charles County County
3.6
/5.0
B+
Good
723
Population
195/sq mi density
$93,250
Median Income
$45,659 per capita
$254,700
Home Value
$256,371 Zillow
$617
Median Rent
17.9% income on rent
56°F
Avg Temperature
302 sunny days/yr
475
Violent Crime/100K
2,215 property/100K
B+
Overall
3.6 / 5.0
Good overall score based on economy, affordability, safety and education
A+
Economy
4.9 / 5.0
$93,250 median income, 1.0% unemployment
A+
Affordability
5.0 / 5.0
$254,700 home value, $617/mo rent
F
Safety
1.0 / 5.0
475 violent crimes/100K (25% above avg)
B+
Education
3.6 / 5.0
32.8% bachelor's degree or higher
Grafton enjoys a temperate climate with an average annual temperature of 56°F (13°C). Winters average 31°F in January while summers reach 79°F in July. The area gets 302 sunny days per year. Annual precipitation totals 39.4 inches. Air quality is rated Good with a median AQI of 43.
Temperature
31°F Jan (-1°C)
79°F Jul (26°C)
| Annual Average | 56.1°F |
| 4% above US avg | |
| January Average | 31°F (-1°C) |
| July Average | 79°F (26°C) |
| Sunny Days | 302 days/yr |
Geography
| Elevation | 746 ft (227 m) |
| Area | 3.7 sq mi (9.6 km²) |
| Population Density | 195/sq mi |
| Coordinates | 38.9765°N, 90.4257°W |
| Timezone | America/Chicago |
| County | St. Charles County County |
| Nearest Airport | St Louis Lambert International (STL) 16 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Air Pollutants (EPA 2023)
| Ozone (O₃) | 0.0484 ppm |
| SO₂ (Sulfur Dioxide) | 1.02 ppb |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 92.6 / 100 |
| Social Vulnerability | 10.6 / 100 |
| Community Resilience | 95.1 / 100 |
Hazard Breakdown
| Tornado | Relatively High |
| Hurricane | Very Low |
| Earthquake | Relatively Moderate |
| Wildfire | Very Low |
| Flood | Relatively High |
| Hail | Relatively High |
| Strong Wind | Very High |
| Heat Wave | Relatively Moderate |
| Winter Weather | Relatively High |
| Lightning | Relatively High |
| Ice Storm | Relatively Moderate |
| Drought | Relatively Low |
| Cold Wave | Relatively High |
| Landslide | Relatively Moderate |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 31°F (-1°C) | 1.8 in | Coldest, Driest |
| February | 33°F (1°C) | 2.0 in | |
| March | 44°F (6°C) | 3.4 in | |
| April | 55°F (13°C) | 3.8 in | |
| May | 64°F (18°C) | 4.1 in | Wettest |
| June | 73°F (23°C) | 3.5 in | |
| July | 79°F (26°C) | 3.8 in | Warmest |
| August | 76°F (24°C) | 3.3 in | |
| September | 68°F (20°C) | 3.3 in | |
| October | 57°F (14°C) | 2.8 in | |
| November | 44°F (7°C) | 3.3 in | |
| December | 33°F (0°C) | 2.9 in |
Grafton has a seasonal temperature swing of 48°F / from 31°F in January to 79°F in July. Total annual precipitation is 38.0 inches, with May being the wettest month (4.1") and January the driest (1.8").