There are several solar terms in which the day is as long as the night.

Two, namely the vernal equinox and the autumnal equinox.

The traditional 24 solar terms in China mainly reflect the changes of seasons and climate. Among them, some solar terms are long days and short nights, and some solar terms are short days and long nights.

There is a folk saying that "the vernal equinox and the autumnal equinox are equally divided day and night". Among them, at the vernal equinox, when the sun reaches the longitude of 0, the sun shines directly at the equator at the vernal equinox, and at the autumnal equinox, the sun reaches the longitude of 180, which also shines directly at the equator of the earth. The vernal equinox and autumnal equinox, also known as equinox, are common phenomena, when the length of day and night in the northern and southern hemispheres is almost equal.

The longest solar term in a day is the summer solstice. On the summer solstice, the sun shines directly to the northernmost part of the year, so the days are the longest and the nights are the shortest. The longest solar term at night is the solstice in winter, which is contrary to the solstice in summer and indicates the arrival of cold winter. The shortest day and the longest night.

The difference between vernal equinox and autumnal equinox:

1, climate characteristics

The vernal equinox indicates that the chill in winter has faded and the temperature rises rapidly, especially in North China and Huanghuai Plain. The daily average temperature rises to above 10℃ almost at the same time as the rainy areas along the Yangtze River and the south of the Yangtze River, and enters a bright spring.

In the autumn equinox, most parts of China entered a cool autumn. The cold air from the south meets the gradually decaying warm and humid air, which leads to precipitation again and again and the temperature drops again and again.

2. These three periods are different

The vernal equinox is third-class, waiting for the mysterious bird to arrive; Second, wait for Lei Nai to make a sound; Third, wait for the power to start. The autumn equinox is third-class, and the thunder stops; Second, wait for scorpion blank households; Wait for the water to dry.

3. Different definitions

"Spring and Autumn Stories Up and Down of Yin and Yang" said: "The vernal equinox, Yin and Yang are also half-phase, so it is cold and summer day and night." It means that day and night are equally divided, each being 12 hours. Second, in ancient times, it was spring from beginning of spring to long summer, and the vernal equinox was in the three months of spring, and the spring was equally divided.

"Spring and Autumn Stories Yin and Yang in and out" said: "The autumn equinox, Yin and Yang are also half-phase, so it is cold and summer day and night." The autumnal equinox means "half" This day is the same as the vernal equinox, but the autumnal equinox divides autumn equally.