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St. Jacob, IL
Full City Profile · Illinois · Madison County County
4.0
/5.0
A
Great
1,617
Population
1,902/sq mi density
$107,188
Median Income
$37,519 per capita
$192,400
Home Value
$248,772 Zillow
$1,260
Median Rent
35.5% income on rent
58°F
Avg Temperature
293 sunny days/yr
A
Overall
4.0 / 5.0
Strong
A+
Economy
5.0 / 5.0
$107,188 median income, 1.5% unemployment
A+
Affordability
5.0 / 5.0
$192,400 home value, $1,260/mo rent
C+
Safety
2.5 / 5.0
0 violent crimes/100K
B+
Education
3.5 / 5.0
31.8% bachelor's degree or higher
St. Jacob 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 | 519 ft (158 m) |
| Area | 0.3 sq mi (0.8 km²) |
| Population Density | 1,902/sq mi |
| Coordinates | 38.7180°N, 89.7633°W |
| Timezone | America/Chicago |
| County | Madison County County |
| Nearest Airport | St Louis Regional (ALN) 19 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) | 2.0 in | Driest |
| February | 33°F (0°C) | 2.2 in | Coldest |
| March | 43°F (6°C) | 3.5 in | |
| April | 54°F (12°C) | 3.7 in | |
| May | 64°F (18°C) | 4.1 in | Wettest |
| June | 73°F (23°C) | 3.8 in | |
| July | 79°F (26°C) | 3.6 in | Warmest |
| August | 75°F (24°C) | 3.2 in | |
| September | 68°F (20°C) | 3.2 in | |
| October | 57°F (14°C) | 2.8 in | |
| November | 45°F (7°C) | 3.2 in | |
| December | 33°F (1°C) | 3.0 in |
St. Jacob has a seasonal temperature swing of 46°F / from 33°F in February to 79°F in July. Total annual precipitation is 38.2 inches, with May being the wettest month (4.1") and January the driest (2.0").