The Tri-State Tornado of 1925 killed 695 people in three states 613 of the victims lived in Illinois. The deadliest tornado on record in the nation occurred largely in Illinois. Illinois is vulnerable to tornadoes with an average of 54 occurring annually, which puts much of the state at around 9.7 tornadoes per 10,000 square miles (30,000 km 2) annually. Illinois averages around 50 days of thunderstorm activity a year which put it somewhat above average for number of thunderstorm days for the United States.

Louis, while the lowest temperature was −38 ☏ (−38.9 ☌), recorded on January 31, 2019, at Mount Carroll. The highest temperature recorded in Illinois was 117 ☏ (47.2 ☌), recorded on July 14, 1954, at East St. Normal annual snowfall exceeds 38 inches or 0.97 m in Chicago, while the southern portion of the state normally receives less than 14 inches or 0.36 m. Average yearly precipitation for Illinois varies from 48 inches or 1,220 mm at the southern tip to 35 inches or 890 mm in the northern portion of the state. Louis, has a humid subtropical climate (Köppen Cfa) with more moderate winters. The southernmost part of the state, from about Carbondale southward, and the eastern suburbs of St.

Most of Illinois has a humid continental climate ( Köppen climate classification Dfa) with hot, humid summers and cool to cold winters. The Climate of Illinois describes the weather conditions, and extremes, noted within the state of Illinois, United States, over time.īecause of its nearly 400-mile (640 km) length and mid-continental location, Illinois has a widely varying climate. Köppen climate types of Illinois, using 1991-2020 climate normals.

The weather feel as il