The first frost is the first of the 24 solar terms.

The first frost is the eighteenth of the twenty-four solar terms and the last solar term in autumn.

Fight with your fingers; The solar calendar is 210; Celebrate every year on 10/23-24 of the Gregorian calendar. After entering the first solar term in first frost, the scene of late autumn is obvious, and cold air moves southward more and more frequently. The first frost does not mean "frost", but refers to the sudden drop in temperature and the large temperature difference between day and night. On the national average, "first frost" is the season with the largest temperature difference between day and night in a year.