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Decatur, IL
Full City Profile · Illinois · Macon County County
3.0
/5.0
B
Good
70,368
Population
1,610/sq mi density
$50,809
Median Income
$31,990 per capita
$97,300
Home Value
$100,881 Zillow
$796
Median Rent
26.5% income on rent
53°F
Avg Temperature
293 sunny days/yr
530
Violent Crime/100K
2,763 property/100K
B
Overall
3.0 / 5.0
Good overall score based on economy, affordability, safety and education
B
Economy
3.2 / 5.0
$50,809 median income, 5.0% unemployment
A+
Affordability
5.0 / 5.0
$97,300 home value, $796/mo rent
F
Safety
1.0 / 5.0
530 violent crimes/100K (40% above avg)
C+
Education
2.7 / 5.0
21.3% bachelor's degree or higher
Decatur experiences four distinct seasons with an average annual temperature of 53°F (12°C). Winters average 27°F in January while summers reach 76°F in July. The area gets 293 sunny days per year. Annual precipitation totals 40.4 inches. The area receives 13.6 inches of snow annually. Air quality is rated Good with a median AQI of 43.
Temperature
27°F Jan (-3°C)
76°F Jul (24°C)
| Annual Average | 53.0°F |
| 2% below US avg | |
| January Average | 27°F (-3°C) |
| July Average | 76°F (24°C) |
| Sunny Days | 293 days/yr |
Geography
| Elevation | 689 ft (210 m) |
| Area | 46.9 sq mi (121.5 km²) |
| Population Density | 1,610/sq mi |
| Coordinates | 39.8560°N, 88.9337°W |
| Timezone | America/Chicago |
| County | Macon County County |
| Nearest Airport | Central Il Regional/Bloomington-Normal (BMI) 43 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Air Pollutants (EPA 2023)
| Ozone (O₃) | 0.0498 ppm |
| SO₂ (Sulfur Dioxide) | 2.66 ppb |
| PM2.5 (Fine Particles) | 9.3 μg/m³ |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 83.3 / 100 |
| Social Vulnerability | 50.8 / 100 |
| Community Resilience | 91.0 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Hurricane | Very Low |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Relatively Moderate |
| Hail | Relatively Moderate |
| Strong Wind | Relatively High |
| Heat Wave | Relatively Moderate |
| Winter Weather | Relatively Moderate |
| Lightning | Relatively Moderate |
| Ice Storm | Relatively Moderate |
| Drought | Relatively Moderate |
| Cold Wave | Relatively High |
| Landslide | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 27°F (-3°C) | 1.9 in | Coldest, Driest |
| February | 30°F (-1°C) | 1.9 in | |
| March | 41°F (5°C) | 3.3 in | |
| April | 53°F (11°C) | 3.9 in | |
| May | 63°F (17°C) | 4.3 in | Wettest |
| June | 72°F (22°C) | 3.9 in | |
| July | 76°F (24°C) | 4.3 in | Warmest |
| August | 74°F (23°C) | 3.8 in | |
| September | 67°F (19°C) | 3.2 in | |
| October | 55°F (13°C) | 2.8 in | |
| November | 42°F (6°C) | 3.2 in | |
| December | 31°F (-1°C) | 2.9 in |
Decatur has a seasonal temperature swing of 49°F / from 27°F in January to 76°F in July. Total annual precipitation is 39.2 inches, with May being the wettest month (4.3") and January the driest (1.9").