You may have heard that sunburning happens fastest during the midday hours. That is, the hours around noon. That's when the sun is highest in the sky, so its rays are most direct and thus most intense.

But have you noticed that the highest temperature of the day usually doesn't occur until later in the afternoon. In fact, the high temperature today probably occurred sometime after 3pm.

So why doesn't the day's highest temperature coincide with the most intense sunlight? The answer has to do with the way air heats up. The sun doesn't really heat the air directly - instead, the sun heats the ground, and the ground heats the air. Just like cold pizza takes time to heat up in the oven, the ground takes time to heat up from sunshine. And then it takes time for the ground to heat the air. This step-by-step heating creates a delay of a few hours between the time of the most intense sunlight and the time of the day's highest temperature.

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