December 3rd marked the date of the city’s latest-in-the-year 70-degree day, occurring on two occasions since 1871, first in 1970 and again in 2012. The earliest-in-the-year occurrence was in 1999 on February 11. Barring an unprecedented surge of warmth, Chicagoans can reasonably expect more than two months to elapse until the city’s next 70° day.
