Flat Rock, IL
Full City Profile · Illinois · Lawrence County County
3.4
/5.0
B
Good
362
Population
421/sq mi density
$49,881
Median Income
$28,516 per capita
$56,700
Home Value
$106,877 Zillow
56°F
Avg Temperature
B
Overall
3.4 / 5.0
Good overall score based on economy, affordability, safety and education
B
Economy
3.2 / 5.0
$49,881 median income, 6.5% unemployment
A+
Affordability
5.0 / 5.0
$56,700 home value, /mo rent
C
Education
2.1 / 5.0
13.4% bachelor's degree or higher
Flat Rock enjoys a temperate climate with an average annual temperature of 56°F (13°C). Winters average 31°F in January while summers reach 77°F in July. Annual precipitation totals 41.7 inches. The area receives 11.6 inches of snow annually.
Temperature
31°F Jan (-0°C)
77°F Jul (25°C)
| Annual Average | 55.7°F |
| 3% above US avg | |
| January Average | 31°F (-0°C) |
| July Average | 77°F (25°C) |
Geography
| Elevation | 500 ft (152 m) |
| Area | 0.9 sq mi (2.2 km²) |
| Population Density | 421/sq mi |
| Coordinates | 38.9037°N, 87.6734°W |
| Timezone | America/Chicago |
| County | Lawrence County County |
| Nearest Airport | Lawrenceville-Vincennes International (LWV) 10 miles away |
Precipitation & Snow
Air Quality
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 49.2 / 100 |
| Social Vulnerability | 57.4 / 100 |
| Community Resilience | 47.3 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Very Low |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Very Low |
| Strong Wind | Relatively Low |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| Ice Storm | Relatively Low |
| Drought | Relatively Moderate |
| Cold Wave | Relatively Low |
| Landslide | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 31°F (-0°C) | 3.2 in | Coldest |
| February | 35°F (2°C) | 2.2 in | Driest |
| March | 45°F (7°C) | 3.2 in | |
| April | 56°F (13°C) | 4.2 in | |
| May | 66°F (19°C) | 4.9 in | Wettest |
| June | 75°F (24°C) | 4.4 in | |
| July | 77°F (25°C) | 4.2 in | Warmest |
| August | 76°F (24°C) | 2.9 in | |
| September | 69°F (21°C) | 2.9 in | |
| October | 58°F (14°C) | 3.5 in | |
| November | 45°F (7°C) | 3.4 in | |
| December | 35°F (2°C) | 2.7 in |
Flat Rock has a seasonal temperature swing of 46°F / from 31°F in January to 77°F in July. Total annual precipitation is 41.7 inches, with May being the wettest month (4.9") and February the driest (2.2").