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Weather & Climate in Lake Petersburg, IL
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Lake Petersburg experiences four distinct seasons with an average annual temperature of 52°F (11°C). Winters average 26°F in January while summers reach 75°F in July. The area gets 302 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Annual precipitation totals 38.4 inches. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 594 feet.
Temperature
26°F Jan (-3°C)
75°F Jul (24°C)
| Annual Average | 52.0°F |
| 4% below US avg | |
| January Average | 26°F (-3°C) |
| July Average | 75°F (24°C) |
| Sunny Days | 302 days/yr |
Geography
| Elevation | 594 ft (181 m) |
| Area | 2.0 sq mi (5.3 km²) |
| Population Density | 425/sq mi |
| Coordinates | 39.9843°N, 89.8562°W |
| Timezone | America/Chicago |
| County | Sangamon County County |
| Nearest Airport | General Downing - Peoria International (PIA) 48 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
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)
Earthquake History
6 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.4.
| Mar 2, 1990 | 9 km NW of Vernon, Illinois | M3.4 | 139 km | 0 km |
| May 13, 2025 | 7 km SSW of Lerna, Illinois | M3.3 | 148 km | 10 km |
| Jan 29, 1993 | 7 km WNW of Brownstown, Illinois | M3.2 | 127 km | 5 km |
| Jul 1, 2017 | 9 km SSE of Mulberry Grove, Illinois | M3.1 | 137 km | 17 km |
| Sep 5, 2004 | 3 km WNW of Saint Peter, Illinois | M2.9 | 148 km | 33 km |
| Sep 19, 2024 | 1 km S of Old Monroe, Missouri | M2.6 | 141 km | 2 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
734 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 22 fatalities, 863 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Nov 17, 2013 | EF4 | 75 km | 46.4 mi | 3 |
| May 13, 1995 | EF4 | 57 km | 7.0 mi | 0 |
| May 5, 1977 | EF4 | 59 km | 7.3 mi | 0 |
| Jun 29, 1976 | EF4 | 91 km | 4.9 mi | 0 |
| Mar 20, 1976 | EF4 | 92 km | 63.7 mi | 0 |
| Jun 14, 1957 | EF4 | 29 km | 4.3 mi | 2 |
| Apr 4, 2023 | EF3 | 55 km | 19.9 mi | 0 |
| Dec 1, 2018 | EF3 | 75 km | 12.5 mi | 0 |
| Apr 19, 2011 | EF3 | 60 km | 4.3 mi | 0 |
| Dec 31, 2010 | EF3 | 1 km | 3.6 mi | 0 |
| Aug 19, 2009 | EF3 | 25 km | 24.3 mi | 0 |
| May 10, 2003 | EF3 | 56 km | 17.5 mi | 0 |
| Jun 1, 1999 | EF3 | 76 km | 10.0 mi | 1 |
| Apr 19, 1996 | EF3 | 61 km | 14.5 mi | 0 |
| Apr 19, 1996 | EF3 | 57 km | 9.4 mi | 0 |
| May 13, 1995 | EF3 | 49 km | 25.0 mi | 0 |
| May 9, 1995 | EF3 | 16 km | 50.0 mi | 0 |
| May 1, 1983 | EF3 | 84 km | 4.0 mi | 0 |
| Jun 21, 1981 | EF3 | 71 km | 8.8 mi | 1 |
| Jul 26, 1978 | EF3 | 22 km | 8.9 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 26°F (-3°C) | 1.5 in | Coldest, Driest |
| February | 30°F (-1°C) | 1.7 in | |
| March | 41°F (5°C) | 3.1 in | |
| April | 53°F (12°C) | 3.6 in | |
| May | 63°F (17°C) | 4.3 in | Wettest |
| June | 72°F (22°C) | 3.8 in | |
| July | 75°F (24°C) | 3.7 in | Warmest |
| August | 74°F (23°C) | 3.4 in | |
| September | 67°F (19°C) | 3.4 in | |
| October | 55°F (13°C) | 2.7 in | |
| November | 42°F (5°C) | 3.0 in | |
| December | 30°F (-1°C) | 2.6 in |
Lake Petersburg has a seasonal temperature swing of 49°F / from 26°F in January to 75°F in July. Total annual precipitation is 36.9 inches, with May being the wettest month (4.3") and January the driest (1.5").