Why does the weather forecast say the highest temperature today and the lowest temperature tomorrow?

Weather stations always report the highest and lowest temperatures when forecasting the weather. As we all know, on sunny days in summer, the hottest time is not at noon, but at two or three o'clock in the afternoon. The lowest temperature is in the early morning.

At noon, the sun shines directly on the ground. Why is the hottest time not noon?

As we know, whether the weather is hot or cold is mainly determined by the temperature, and the main factor affecting the temperature is determined by the intensity of solar radiation. However, solar photothermal is not the main reason for directly increasing the temperature. The direct absorption of sunlight by air is only about 14%, and about 43% is absorbed by the ground. When the ground absorbs solar radiation heat, it is conducted into the air through radiation, convection and other forms, which is the main reason for the temperature rise.

The sun shines on the ground to make it hot, and the heat absorbed by the ground is released to make the air hot, so it takes some time for the temperature to rise after the ground gets hot. After noon, when the heat released from the ground is still less than the heat provided by the sun, the ground temperature will not rise to the highest until two or three o'clock in the afternoon, and the temperature is also the highest.

In the same way, after the sun went down, it lost the supply of sunlight and heat, so it began to lose heat continuously and the air flow was also decreasing. The ground temperature drops to the lowest value in the morning, so the temperature is the lowest at this time.