Dear Tom,

What have been Chicago's temperature extremes recorded so far in 2011?

—Terry Kaap

Dear Terry,

Chicago's vigorous continental climate allows for wide swings in temperature during the year. So far in 2011, the city's official temperatures as recorded at O'Hare International Airport have spanned a substantial range of 108 degrees — from steamy back-to-back 99-degree highs on July 20-21 to a chilling low of minus 9 on Feb. 10. In any one calendar year, the city's largest range of extremes is 126 degrees, logged in 1985 from a low of minus 27 on Jan. 20 to a high of 99 on Sept. 7. Covering Chicago's entire 141-year climate history dating to 1871, the city's all-time temperature extremes have encompassed 132 degrees — ranging from minus 27 on Jan. 20, 1985 to 105 on July 24, 1934.