When is the sunrise in summer?

China has a large land area, spanning from north to south and from east to west. During the summer half year (from vernal equinox to autumnal equinox), the sunrise time gradually changes from south to north. Hainan is usually around 5: 40 from the summer solstice at the earliest, while Heilongjiang in the northeast will be around 3: 00 in advance.

For most parts of the earth except the equator and poles and their vicinity, the earliest day of sunrise is before the summer solstice, the latest day of sunset is after the summer solstice, the earliest day of sunset is before the winter solstice and the latest day of sunrise is after the winter solstice.

The time of sunrise and sunset can be calculated by tracking the sun's trajectory, but the calculated time will be slightly different from the real feeling, the calculated sunshine time will be longer than the real feeling, and the calculated night time will be shorter than the real feeling.

Because sunlight is refracted by the influence of the earth's atmosphere, people have seen the sunrise before the sun rises above the horizon, which is an illusion generated at sunrise every day. Astronomers in ancient China recorded a rare astronomical phenomenon called "the sky rises again", which means that it appears for two days in a row on the same day. It is usually an astronomical spectacle caused by a total solar eclipse from 5 am to 7 am. At the first sunrise, the sky gradually darkened, and then the next sunrise came.