According to the National Atmospheric and Oceanic Administration, the hottest time of the day changes with the time of year and the latitude of the location in question. For a typical summer afternoon, says NOAA, the hottest time of day is usually in the mid-afternoon.
The National Atmospheric and Oceanic Administration claims that the amount of lag between 12:00 PM and the hottest time of day can be as much as three or four hours. The reason for this difference is the change in the earth's axis. The intensity of the heat experienced on Earth's surface at this time will vary based on location.