What is the hottest time of the day?

Dear Tom,

What is the hottest time of the day?
— Avery Lenk
Dear Avery,
Chicago’s weather, as changeable as it is, does have some averages that are quite reliable and can be depended upon to produce fairly regular results. The average time of the day at which the high temperature is reached is one of those variables, at least during the summer. On average, Chicago experiences its daily maximum temperature around 3:30 p.m. Let me stress, though, that this is only an average. The time of the maximum temperature can vary considerably when the weather is inclement, and this happens much more frequently during the winter and less frequently in the summer. In July, the maximum temperature is reached between 2 p.m. and 5 p.m. about 70 percent of the time, but it in January it’s only 30 percent of the time.