Johnston City, IL
Full City Profile · Illinois · Williamson County County
3.7
/5.0
B+
Good
3,351
Population
1,581/sq mi density
$46,629
Median Income
$33,916 per capita
$84,500
Home Value
$105,413 Zillow
$830
Median Rent
39.5% income on rent
56°F
Avg Temperature
B+
Overall
3.7 / 5.0
Good overall score based on economy, affordability, safety and education
B
Economy
3.2 / 5.0
$46,629 median income, 3.9% unemployment
A+
Affordability
5.0 / 5.0
$84,500 home value, $830/mo rent
C+
Education
2.8 / 5.0
21.9% bachelor's degree or higher
Johnston City enjoys a temperate climate with an average annual temperature of 56°F (13°C). Winters average 33°F in January while summers reach 78°F in July. Annual precipitation totals 45.9 inches. The area receives 9.8 inches of snow annually.
Temperature
33°F Jan (1°C)
78°F Jul (26°C)
| Annual Average | 56.4°F |
| 4% above US avg | |
| January Average | 33°F (1°C) |
| July Average | 78°F (26°C) |
Geography
| Elevation | 440 ft (134 m) |
| Area | 0.8 sq mi (2.1 km²) |
| Population Density | 1,581/sq mi |
| Coordinates | 37.8210°N, 88.9293°W |
| Timezone | America/Chicago |
| County | Williamson County County |
| Nearest Airport | Barkley Regional (PAH) 53 miles away |
Precipitation & Snow
Air Quality
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 85.8 / 100 |
| Social Vulnerability | 55.4 / 100 |
| Community Resilience | 78.2 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Hurricane | Very Low |
| Earthquake | Relatively Moderate |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Relatively Moderate |
| Strong Wind | Very High |
| Heat Wave | Relatively Moderate |
| Winter Weather | Relatively High |
| Lightning | Relatively Moderate |
| Ice Storm | Relatively Moderate |
| Drought | Relatively Low |
| Cold Wave | Relatively Moderate |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 33°F (1°C) | 3.0 in | Coldest |
| February | 38°F (3°C) | 2.8 in | Driest |
| March | 47°F (8°C) | 4.3 in | |
| April | 57°F (14°C) | 5.2 in | Wettest |
| May | 66°F (19°C) | 4.7 in | |
| June | 75°F (24°C) | 4.3 in | |
| July | 78°F (26°C) | 3.7 in | Warmest |
| August | 76°F (24°C) | 3.5 in | |
| September | 68°F (20°C) | 3.3 in | |
| October | 57°F (14°C) | 3.7 in | |
| November | 46°F (8°C) | 4.0 in | |
| December | 37°F (3°C) | 3.5 in |
Johnston City has a seasonal temperature swing of 45°F / from 33°F in January to 78°F in July. Total annual precipitation is 45.9 inches, with April being the wettest month (5.2") and February the driest (2.8").