Did you know?
Illinois Weather and Climate Statistics and Trends
- Illinois experiences an average of five severe winter storms during the November-April period. These storms may consist of only heavy snow, or snow and ice mixed, or only ice. Although five is the average number of storms, as many as 18 (1977-1978) and as few as two (1921-1922) have occurred in one winter.
- A study of the number of times that severe winter storms have occurred on each date reveals that December 24, 25, and 26, and March 2 and 3 are high-incidence periods. There are two chances in 10 that a severe winter storm will occur somewhere in the state on these dates.
- The most snow from a single storm occurred in Astoria on February 27-28, 1900 with 37.8 inches.
- The most snow for a single winter was 105.1 inches at Antioch during the winter of 1978-1979.
- The lowest temperature reported in Illinois was -36 degrees in Congerville on January 5, 1999.
- Northern Illinois averages 140 days of temperatures at or below 32 degrees, while southern Illinois experiences an average of 80 days at or below freezing.
- The highest temperature reported in Illinois was 117 degrees in East St. Louis on July 14, 1954.
- The 1995 heat wave, the deadliest on record, led to 753 deaths.
- Two to three deaths and eight serious injuries are attributed to lightning each year in Illinois.
- The days of the week with the most incidents are Saturday, Sunday, and Wednesday, and occur most often from 2 p.m. to 6 p.m.
- Eighty-five percent of lightning victims are children and young men (ages 10-35), usually engaged in recreation or outside work. Twenty percent of lightning victims die and another 70 percent receive serious injuries. Only 10 percent of lightning victims escape with less serious injuries.
- By definition, a severe thunderstorm contains one or more of the following: hail at least 1 inch in diameter, wind gusts 58 mph or higher, or a tornado.
- It is estimated that there are roughly 1,800 thunderstorms that occur across on planet earth every day.
- The average number of tornadoes in Illinois is 29 per year, but there were none in 1919 and 1933, and as many as 107 tornadoes in 1974.
- Illinois has experienced two of the worst tornadoes in the nation's history: the infamous Tri-State tornado of March 18, 1925, with 695 dead, 2,000 injured, and $130 million in property damage; the Mattoon tornado of May 26, 1917, with 101 dead, 638 injured, and $55 million in property damage.
- The most rainfall from a single event was 16.94 inches in Aurora during a 24-hour period spanning July 17-18, 1996.
- Flood losses in Illinois have averaged $257 million annually since 1983.
- Within Illinois and the Midwest, flood losses have been increasing at a greater rate than elsewhere in the nation.
- Five factors control the climate in Illinois: (1) the sun; (2) weather systems; (3) topography; (4) urban areas; and (5) Lake Michigan.
- Buildings, parking lots, roads, and industrial activities affect the local climate. For example, Chicago tends to be 2 degrees warmer than in the surrounding rural areas, especially at night.
- Lake Michigan tends to moderate temperatures in local areas, causing cooler summers and warmer winters.
| News |
Source: State Climatologist Jim Angel, Illinois State Water Survey; http://www.sws.uiuc.edu
(217) 333-0729; firstname.lastname@example.org
Illinois State Climatologist Web Site: http://www.sws.uiuc.edu/atmos/statecli/