In autumn and winter weather, a regular circle suddenly appeared on the glass, shaped like a focused aperture, as big as a disk, with the feeling of a coordinate point. Is this normal?

Autumn (MBTH) is the third season among the four seasons, and it is the transition season from summer to winter. Autumn in the northern hemisphere is from September to 165438+ 10, and autumn in the southern hemisphere is from March to May.

China traditionally takes "beginning of autumn" in the 24 solar terms as the starting point of autumn and ends with "beginning of winter". Entering autumn means that rainfall and storms tend to decrease or decrease, and everything in nature begins to mature from lush.

Autumn solar terms:

Beginning of autumn is the 13 of the 24 solar terms. On August 7th or 8th every year, beginning of autumn is considered as the time when the sun reaches 135. "Autumn" means that summer is cool, which means the beginning of autumn. But in early autumn, the weather in Jianghuai area is still very hot.

According to the standard of dividing seasons according to the average temperature, it must be that the average temperature for five days is below 22℃ to be considered as autumn. According to this standard, the Jianghuai area generally enters autumn in the middle and late September. After beginning of autumn, although the summer heat is hard to disappear for a while, there is still the afterglow of "autumn tiger", but the general trend is that the weather is getting colder and colder. The daily temperature range is gradually obvious, which is often very hot during the day and very cold at night.