The city lies within the humid continental climate zone
(Köppen: Dfa ), and experiences
four distinct seasons. Summers are hot and humid, with a July daily average of
75.8 °F (24.3 °C). In a normal summer, temperatures exceed 90 °F
(32 °C) on 21 days. Winters are cold and snowy with few sunny days,
and with a January daytime average of 31 °F (−0.6 °C). Spring and
autumn are mild seasons with low humidity.
According to the National Weather Service, Chicago's
highest official
