What is the coldest time of the day?

The coldest time of the day is around four or five in the morning.

After 14:00, the solar radiation gradually decreases, the ground temperature decreases, and the temperature also decreases. After sunset, there is no solar radiation income, only heat expenditure, and the ground temperature continues to decrease until the next day. Before and after sunrise, when solar radiation returns, the temperature reaches the lowest value of the day.

The temperature is affected by the movement of the sun and the rotation of the earth. The earth’s orbit around the sun is an ellipse that is close to a perfect circle. The sun is located at a focus of the elliptical orbit. In this way, within a year or even within a day, the daily Distances are constantly changing.

Compared with the average distance between the sun and the earth (149.6 million kilometers), the change in the distance between the sun and the earth within a year (005 million kilometers) is almost negligible. Then within a day, the change in the distance between the sun and the earth is even more insignificant.

Extended information:

The highest temperature on the mainland generally occurs around 14:00, and the lowest temperature is usually before sunrise. After noon, although the solar radiation begins to weaken, the solar radiation heat gained by the ground is still more than the heat lost by ground radiation.

The heat stored on the ground continues to increase until the heat radiated by the sun begins to be less than the heat lost by ground radiation, that is, when the surplus turns into a deficit, the ground temperature reaches its maximum value.

The ground loses heat at night and the temperature drops. The heat stored on the ground is minimized before sunrise, so the lowest temperature occurs around 5 a.m. in the morning. The difference between the highest and lowest temperatures during the day is called the diurnal temperature range.

Baidu Encyclopedia-Diurnal changes in temperature