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Thomson, IL
Full City Profile · Illinois · Clinton County County
2.8
/5.0
C+
Fair
1,526
Population
687/sq mi density
$54,063
Median Income
$10,875 per capita
$122,300
Home Value
$147,444 Zillow
$940
Median Rent
40.4% income on rent
50°F
Avg Temperature
275 sunny days/yr
88
Violent Crime/100K
1,002 property/100K
C+
Overall
2.8 / 5.0
Fair overall score based on economy, affordability, safety and education
B+
Economy
3.7 / 5.0
$54,063 median income, 2.3% unemployment
A+
Affordability
5.0 / 5.0
$122,300 home value, $940/mo rent
F
Safety
1.0 / 5.0
88 violent crimes/100K
F
Education
1.4 / 5.0
5.2% bachelor's degree or higher
Thomson experiences four distinct seasons with an average annual temperature of 50°F (10°C). Winters average 21°F in January while summers reach 75°F in July. The area gets 275 sunny days per year. Annual precipitation totals 34.3 inches. Air quality is rated Good with a median AQI of 43.
Temperature
21°F Jan (-6°C)
75°F Jul (24°C)
| Annual Average | 49.9°F |
| 8% below US avg | |
| January Average | 21°F (-6°C) |
| July Average | 75°F (24°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 605 ft (184 m) |
| Area | 2.2 sq mi (5.7 km²) |
| Population Density | 687/sq mi |
| Coordinates | 41.9747°N, 90.1122°W |
| Timezone | America/Chicago |
| County | Clinton County County |
| Nearest Airport | Quad Cities International (MLI) 42 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Air Pollutants (EPA 2023)
| Ozone (O₃) | 0.0477 ppm |
| SO₂ (Sulfur Dioxide) | 1.32 ppb |
| PM2.5 (Fine Particles) | 11.0 μg/m³ |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 64.8 / 100 |
| Social Vulnerability | 34.6 / 100 |
| Community Resilience | 87.5 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Hurricane | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Relatively Moderate |
| Strong Wind | Relatively High |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| Ice Storm | Relatively Moderate |
| Drought | Relatively High |
| Cold Wave | Relatively Moderate |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 21°F (-6°C) | 1.4 in | Coldest |
| February | 24°F (-4°C) | 1.4 in | Driest |
| March | 36°F (2°C) | 2.6 in | |
| April | 49°F (9°C) | 3.6 in | |
| May | 60°F (16°C) | 4.3 in | |
| June | 69°F (21°C) | 4.6 in | Wettest |
| July | 75°F (24°C) | 3.7 in | Warmest |
| August | 71°F (22°C) | 4.5 in | |
| September | 63°F (17°C) | 3.5 in | |
| October | 52°F (11°C) | 2.7 in | |
| November | 38°F (3°C) | 2.6 in | |
| December | 25°F (-4°C) | 2.0 in |
Thomson has a seasonal temperature swing of 53°F / from 21°F in January to 75°F in July. Total annual precipitation is 36.9 inches, with June being the wettest month (4.6") and February the driest (1.4").