Plymouth, IL
Full City Profile · Illinois · McDonough County County
2.8
/5.0
C+
Fair
512
Population
898/sq mi density
$39,750
Median Income
$24,923 per capita
$55,500
Home Value
$111,285 Zillow
$796
Median Rent
36.3% income on rent
53°F
Avg Temperature
C+
Overall
2.8 / 5.0
Fair overall score based on economy, affordability, safety and education
D
Economy
1.7 / 5.0
$39,750 median income, 20.3% unemployment
A+
Affordability
5.0 / 5.0
$55,500 home value, $796/mo rent
D
Education
1.7 / 5.0
9.0% bachelor's degree or higher
Plymouth experiences four distinct seasons with an average annual temperature of 53°F (12°C). Winters average 26°F in January while summers reach 76°F in July. Annual precipitation totals 40.2 inches. The area receives 24.1 inches of snow annually.
Temperature
26°F Jan (-3°C)
76°F Jul (25°C)
| Annual Average | 52.8°F |
| 2% below US avg | |
| January Average | 26°F (-3°C) |
| July Average | 76°F (25°C) |
Geography
| Elevation | 644 ft (196 m) |
| Area | 0.2 sq mi (0.6 km²) |
| Population Density | 898/sq mi |
| Coordinates | 40.2921°N, 90.9163°W |
| Timezone | America/Chicago |
| County | McDonough County County |
| Nearest Airport | Quincy Regional-Baldwin Field (UIN) 28 miles away |
Precipitation & Snow
Air Quality
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 37.5 / 100 |
| Social Vulnerability | 61.9 / 100 |
| Community Resilience | 74.3 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Very Low |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Very Low |
| Hail | Relatively Moderate |
| Strong Wind | Relatively Moderate |
| Heat Wave | Relatively Moderate |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| Ice Storm | Relatively Moderate |
| Drought | Relatively Moderate |
| Cold Wave | Relatively Moderate |
| Landslide | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 26°F (-3°C) | 1.9 in | Coldest, Driest |
| February | 30°F (-1°C) | 2.0 in | |
| March | 41°F (5°C) | 2.8 in | |
| April | 53°F (12°C) | 4.2 in | |
| May | 64°F (18°C) | 5.0 in | Wettest |
| June | 73°F (23°C) | 4.7 in | |
| July | 76°F (25°C) | 4.2 in | Warmest |
| August | 74°F (24°C) | 4.1 in | |
| September | 67°F (20°C) | 3.6 in | |
| October | 55°F (13°C) | 3.1 in | |
| November | 42°F (6°C) | 2.7 in | |
| December | 31°F (-0°C) | 2.0 in |
Plymouth has a seasonal temperature swing of 51°F / from 26°F in January to 76°F in July. Total annual precipitation is 40.2 inches, with May being the wettest month (5.0") and January the driest (1.9").