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Cortland, IL
Full City Profile · Illinois · DeKalb County County
3.4
/5.0
B
Good
4,556
Population
1,269/sq mi density
$82,750
Median Income
$35,862 per capita
$203,700
Home Value
$284,621 Zillow
$1,420
Median Rent
32.2% income on rent
49°F
Avg Temperature
275 sunny days/yr
46
Violent Crime/100K
984 property/100K
B
Overall
3.4 / 5.0
Good overall score based on economy, affordability, safety and education
A
Economy
4.3 / 5.0
$82,750 median income, 4.6% unemployment
A+
Affordability
5.0 / 5.0
$203,700 home value, $1,420/mo rent
F
Safety
1.0 / 5.0
46 violent crimes/100K
B
Education
3.5 / 5.0
31.1% bachelor's degree or higher
Cortland experiences four distinct seasons with an average annual temperature of 49°F (9°C). Winters average 21°F in January while summers reach 73°F in July. The area gets 275 sunny days per year. Annual precipitation totals 37.3 inches. The area receives 33.1 inches of snow annually. Air quality is rated Good with a median AQI of 43.
Temperature
21°F Jan (-6°C)
73°F Jul (23°C)
| Annual Average | 48.6°F |
| 10% below US avg | |
| January Average | 21°F (-6°C) |
| July Average | 73°F (23°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 890 ft (271 m) |
| Area | 3.6 sq mi (9.3 km²) |
| Population Density | 1,269/sq mi |
| Coordinates | 41.9372°N, 88.6893°W |
| Timezone | America/Chicago |
| County | DeKalb County County |
| Nearest Airport | Chicago/Rockford International (RFD) 27 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 80.8 / 100 |
| Social Vulnerability | 29.2 / 100 |
| Community Resilience | 75.9 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Hurricane | Very Low |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Relatively Moderate |
| Hail | Relatively Low |
| Strong Wind | Relatively Moderate |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| 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 | 21°F (-6°C) | 1.5 in | Coldest |
| February | 25°F (-4°C) | 1.2 in | Driest |
| March | 36°F (2°C) | 2.5 in | |
| April | 48°F (9°C) | 3.7 in | |
| May | 60°F (15°C) | 3.8 in | |
| June | 69°F (21°C) | 4.3 in | Wettest |
| July | 73°F (23°C) | 4.1 in | Warmest |
| August | 71°F (21°C) | 4.1 in | |
| September | 63°F (17°C) | 3.9 in | |
| October | 51°F (11°C) | 2.6 in | |
| November | 38°F (3°C) | 2.9 in | |
| December | 25°F (-4°C) | 2.1 in |
Cortland has a seasonal temperature swing of 53°F / from 21°F in January to 73°F in July. Total annual precipitation is 36.5 inches, with June being the wettest month (4.3") and February the driest (1.2").