When do the highest and lowest temperatures appear in a day?

In a day, the highest temperature is around 2 pm, and the lowest temperature is around sunrise.

1, whether the weather is hot or cold mainly depends on the temperature, and the fundamental factor affecting the temperature is the intensity of solar radiation. Solar photothermal is not the main reason for the direct temperature rise. The direct absorption of solar heat energy by air is only about 14%, while 43% of the energy in the visible region 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.

2. After noon, the solar radiation began to weaken, but the ground still absorbed more heat than it consumed. Until about 1 in the afternoon, the ground temperature reached the highest and the ground radiation reached the strongest. Because it takes a certain time for heat to transfer from the ground to the atmosphere, the temperature near the ground reaches the highest at about 2 pm, and the atmospheric reverse radiation also reaches the maximum in a day.

3. Similarly, the atmosphere mainly loses heat in the form of inverse radiation and atmospheric radiation, and there is no solar radiation to supplement heat before the next sunrise, so the temperature reaches the lowest value of the day before and after the next sunrise.

Extended data:

Maximum thermometer

Maximum thermometer: it is specially used to measure the maximum temperature within a certain time interval. Its structure is that a glass needle is arranged at the bottom of the ball and extends straight to the capillary hole to narrow the capillary hole. As the temperature rises, mercury expands and the pressure increases, forcing mercury to squeeze through the thin tube and rise. When the temperature drops, because there is not enough pressure to make mercury squeeze through the tubule and return to the ball, the mercury column will break at the tubule, so the top of the mercury column above the tubule will keep the highest temperature indicated by the thermometer in the past period of time, so the highest temperature can be measured.

minimum thermometer

Minimum thermometer: it is specially used to measure the minimum temperature within a certain time interval. It uses alcohol as the temperature measuring liquid and puts the cursor in the capillary. When the temperature rises, alcohol can expand on the cursor, and the cursor itself can remain in place because the top has enough friction against the pipe wall. When the temperature drops and the alcohol column shrinks to contact with the top of the cursor, the cursor will not break through the top of the alcohol column because the surface tension of the alcohol liquid surface is greater than the friction of the cursor on the pipe wall, and the cursor will be driven to slide downwards by the surface tension of the liquid surface. In other words, the cursor can only be lowered, not raised. Therefore, the indicator of the cursor from the far end of the ball is the lowest temperature that has occurred in a certain time interval.