July Liuhuo is a Chinese idiom, which means that when the weather turns cool in July of the lunar calendar, when it is just dark, you can see the big Mars falling from the West. Because people mistakenly understand "July" as July of the Gregorian calendar, "July Liuhuo" is also used to describe the hot weather in modern times.
"July flowing fire" does not mean that there is fire in the sky in July (I'm afraid it will be a great disaster). This phrase comes from the "national wind · Fufeng · July" in the book of Songs: "fire flows in July and clothes are given in September". July Liuhuo in the book of songs describes the scene nearly 4000 years ago. Due to the precession, our predecessors and the celestial phenomena we see today are different. At that time, July was roughly equivalent to August and September of today's Gregorian calendar.
On July 12, 2005, Yu Muming gave a speech at Renmin University of China. Ji Baocheng, President of the National People's Congress, said in his welcoming speech: "July is hot, but what is full of enthusiasm is not just the weather". This incident triggered a wider discussion on the correct use of "July Liuhuo" and even on the revival of Sinology. Some people claim that this is a misuse and is inconsistent with the practice of Renmin University in promoting the revival of Sinology, so it should be corrected.