Rochester, IL
Full City Profile · Illinois · Sangamon County County
3.9
/5.0
B+
Good
3,784
Population
1,412/sq mi density
$112,689
Median Income
$47,562 per capita
$241,900
Home Value
$298,141 Zillow
$1,333
Median Rent
22.5% income on rent
54°F
Avg Temperature
77
Violent Crime/100K
537 property/100K
B+
Overall
3.9 / 5.0
Good overall score based on economy, affordability, safety and education
A+
Economy
4.8 / 5.0
$112,689 median income, 3.6% unemployment
A+
Affordability
5.0 / 5.0
$241,900 home value, $1,333/mo rent
F
Safety
1.0 / 5.0
77 violent crimes/100K
A+
Education
5.0 / 5.0
49.9% bachelor's degree or higher
Rochester experiences four distinct seasons with an average annual temperature of 54°F (12°C). Winters average 28°F in January while summers reach 77°F in July. Annual precipitation totals 37.4 inches. The area receives 21.8 inches of snow annually. Air quality is rated Good with a median AQI of 41.
Temperature
28°F Jan (-2°C)
77°F Jul (25°C)
| Annual Average | 54.0°F |
| 0% below US avg | |
| January Average | 28°F (-2°C) |
| July Average | 77°F (25°C) |
Geography
| Elevation | 580 ft (177 m) |
| Area | 0.9 sq mi (2.4 km²) |
| Population Density | 1,412/sq mi |
| Coordinates | 39.7458°N, 89.5665°W |
| Timezone | America/Chicago |
| County | Sangamon County County |
| Nearest Airport | Central Il Regional/Bloomington-Normal (BMI) 61 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 41.0 |
| Rating | Good |
| Good Days % | 71.9% |
| Unhealthy Days | 1 |
Air Pollutants (EPA 2023)
| Ozone (O₃) | 0.0483 ppm |
| PM2.5 (Fine Particles) | 8.9 μg/m³ |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 91.7 / 100 |
| Social Vulnerability | 32.0 / 100 |
| Community Resilience | 92.2 / 100 |
Hazard Breakdown
| Tornado | Relatively High |
| Hurricane | Very Low |
| Earthquake | Relatively Moderate |
| Wildfire | Very Low |
| Flood | Relatively Moderate |
| Hail | Relatively High |
| Strong Wind | Relatively High |
| Heat Wave | Relatively Moderate |
| Winter Weather | Relatively High |
| Lightning | Relatively High |
| Ice Storm | Relatively Moderate |
| Drought | Relatively High |
| Cold Wave | Relatively High |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 28°F (-2°C) | 2.0 in | Coldest, Driest |
| February | 32°F (0°C) | 2.1 in | |
| March | 43°F (6°C) | 2.6 in | |
| April | 54°F (12°C) | 3.9 in | |
| May | 65°F (18°C) | 4.5 in | Wettest |
| June | 74°F (23°C) | 4.5 in | |
| July | 77°F (25°C) | 3.7 in | Warmest |
| August | 75°F (24°C) | 3.0 in | |
| September | 68°F (20°C) | 3.0 in | |
| October | 56°F (13°C) | 3.1 in | |
| November | 44°F (6°C) | 2.9 in | |
| December | 33°F (0°C) | 2.1 in |
Rochester has a seasonal temperature swing of 49°F / from 28°F in January to 77°F in July. Total annual precipitation is 37.4 inches, with May being the wettest month (4.5") and January the driest (2.0").