About what time is dawn in September?

The autumnal equinox is in September, so in September the day and night are almost equinoxed before the autumnal equinox, so the sunrise will be around 6 o'clock Beijing time at dawn.

In addition, because our country spans a relatively large territory and spans several time zones, the time of dawn will vary depending on the time zone.

The sunrise in the northern region in September is around 6:20 in the morning. For example, in northern cities such as Beijing, Tianjin, and Hebei, the earliest sunrise is around 4:50 am in early June, around 5:40 am in early August, and 6:20 am during the autumnal equinox in September. about.

The reason why the sky is bright

Because of the scattering principle of the sun. The first thing to realize is that the sun is an extremely powerful light source—it's much brighter than the moon. Secondly, the nitrogen atoms and oxygen atoms in the atmosphere will have a certain effect on the sunlight that passes through them.

There is a physical phenomenon called Rayleigh scattering that causes light to scatter when it passes through particles with a diameter equal to one-tenth the wavelength (color) of the light. Sunlight is made up of a variety of different colors of light, but blue is much more diffuse than other colors due to the presence of some elements in the atmosphere.

When you look at the sky on a clear day, you will see the sun as a bright disk. The blue color of the entire sky is the color of all the atoms in the atmosphere that scatter blue light. Since red, yellow, green, and other colors of light have very low scattering, the sky you see is blue.