When asked, it is already July fire; To get the letter, you must pass a tung leaf first.

This is a couplet describing the solar terms, and the solar terms described are beginning of autumn.

By the time we care about each other, the weather has turned cold, and we have received letters from afar. Before spreading the letters, we have already greeted each other with tung leaves.

Fire in July comes from The Book of Songs, which has a national style and describes the scenes of ancient people's farming life in detail, and has strong research value. "September is coming, it's almost winter, so we should start making cotton-padded clothes to keep out the cold. It can be seen that "Fire in July" actually describes the change of the four seasons.

The word "fire" in July is the name of the star, also called "fire", which means downward, and "fire in July" means that July of the lunar calendar is the first month of autumn. At this time, Mars is descending from the west, and the weather is getting cold.

Extended data:

The reason why "July filariasis" was misused by the public.

1, "fire" is easily reminiscent of fire in the general sense, but I don't know that "fire" in the poem was the name of a star in ancient times, referring to the brightest star in Scorpio.

2. Different calendars.

The solar calendar (Gregorian calendar) is widely used. July in the solar calendar is a season of unbearable heat. No wonder people associate "July filariasis" with heat.

People in ancient times used the lunar calendar. In the lunar calendar, January, February and March represent spring, April, May and June are summer, July, August and September are autumn, and October and December are winter. Therefore, July in the lunar calendar is equivalent to August and September in the solar calendar, which is exactly the time when summer enters autumn and it turns from hot to cold.