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Grantfork, IL
Full City Profile · Illinois · Madison County County
4.2
/5.0
A
Great
468
Population
1,265/sq mi density
$103,750
Median Income
$48,353 per capita
$195,500
Home Value
$189,276 Zillow
58°F
Avg Temperature
293 sunny days/yr
A
Overall
4.2 / 5.0
Strong
A+
Economy
4.8 / 5.0
$103,750 median income, 3.4% unemployment
A+
Affordability
5.0 / 5.0
$195,500 home value, /mo rent
C+
Safety
2.5 / 5.0
0 violent crimes/100K
A+
Education
4.6 / 5.0
45.4% bachelor's degree or higher
Grantfork enjoys a temperate climate with an average annual temperature of 58°F (14°C). Winters average 34°F in January while summers reach 79°F in July. The area gets 293 sunny days per year. Annual precipitation totals 43.4 inches. The area receives 11.2 inches of snow annually. Air quality is rated Good with a median AQI of 43.
Temperature
34°F Jan (1°C)
79°F Jul (26°C)
| Annual Average | 57.7°F |
| 7% above US avg | |
| January Average | 34°F (1°C) |
| July Average | 79°F (26°C) |
| Sunny Days | 293 days/yr |
Geography
| Elevation | 524 ft (160 m) |
| Area | 0.1 sq mi (0.3 km²) |
| Population Density | 1,265/sq mi |
| Coordinates | 38.8264°N, 89.6666°W |
| Timezone | America/Chicago |
| County | Madison County County |
| Nearest Airport | St Louis Regional (ALN) 21 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Air Pollutants (EPA 2023)
| Ozone (O₃) | 0.0502 ppm |
| SO₂ (Sulfur Dioxide) | 1.30 ppb |
| PM2.5 (Fine Particles) | 9.6 μg/m³ |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 93.4 / 100 |
| Social Vulnerability | 25.9 / 100 |
| Community Resilience | 86.2 / 100 |
Hazard Breakdown
| Tornado | Relatively High |
| Hurricane | Very Low |
| Earthquake | Relatively Moderate |
| Wildfire | Very Low |
| Flood | Relatively Moderate |
| Hail | Relatively High |
| Strong Wind | Relatively Moderate |
| Heat Wave | Relatively High |
| Winter Weather | Relatively High |
| Lightning | Relatively High |
| Ice Storm | Relatively Moderate |
| Drought | Relatively Low |
| Cold Wave | Relatively High |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 34°F (1°C) | 1.9 in | Driest |
| February | 33°F (0°C) | 2.2 in | Coldest |
| March | 43°F (6°C) | 3.6 in | |
| April | 54°F (12°C) | 3.7 in | |
| May | 64°F (18°C) | 4.1 in | Wettest |
| June | 73°F (23°C) | 3.9 in | |
| July | 79°F (26°C) | 3.6 in | Warmest |
| August | 75°F (24°C) | 3.0 in | |
| September | 68°F (20°C) | 3.2 in | |
| October | 57°F (14°C) | 2.8 in | |
| November | 45°F (7°C) | 3.4 in | |
| December | 34°F (1°C) | 3.1 in |
Grantfork has a seasonal temperature swing of 47°F / from 33°F in February to 79°F in July. Total annual precipitation is 38.5 inches, with May being the wettest month (4.1") and January the driest (1.9").