Climate of Chicago
The climate of Chicago is classified as hot-summer humid continental (Köppen: Dfa, Trewartha: Dca) with hot humid summers and cold, occasionally snowy winters. Although lakefront areas such as Northerly Island have a Cfa (humid subtropical) climate using Köppen's −3 °C (27 °F) winter isotherm, even those areas are continental (Dca) under Trewartha due to winters averaging below 0 °C (32 °F), and inland areas such as Midway and O'Hare International Airports are continental even under Köppen.