The worst heatwave to affect many parts of the mainland for 140 years has killed dozens of people and led to countrywide heat warnings. Jiangsu province, which hosts the Games from August 16 to 24, experienced its hottest July for 50 years.
"Mainland China is experiencing a record heatwave," says Andrew Li Hei-yin, 16, one of four Hong Kong tennis stars who will play at the Games. "I've read sad news of some people dying from the heat in Nanjing. I'm worried temperatures will still be really high during the event."
He and Eudice Chong, Ng Kwan-yau, and Jack Wong Hong-kit - all members of Hong Kong's junior national squad - will play in the singles and mixed doubles events. Andrew will team up with Eudice in the mixed doubles, with Jack partnering Kwan-yau.
Before the start of the Games, Eudice and Andrew will be playing a warm-up tournament - an International Tennis Federation Grade 2 junior competition from August 6 to 10. It is being staged at the same venue as the Games' tennis event - the Nanjing Sports Institute Tennis Academy.
Andrew, 16, left Diocesan Boys' School this year after only one term in Form Four so that he could focus full-time on tennis training. "The warm-up event will let us get used to the courts. And I'll get the chance to use my new racquets; my old ones were worn out, so I bought a new racquet, which is heavier. It should help me hit more powerful shots without too much effort."
Eudice, 17, says she plans to stay out of the sun in Nanjing when she isn't playing. "Drinking more water will also help us to keep cool."
She says the warm-up event will help her practise playing alongside Andrew. "I've played with different junior players before and won some titles, but never with him."
She officially starts her Year 12 studies at International Christian School on August 8, so will be taking off at least two weeks from school to compete at the Games.
Jack, who at 14 is the youngest of the four, left La Salle College after completing his first term in Form Three there so that he can train full-time. His mixed doubles partner, Kwan-yau, 16, is a Form Four student at Diocesan Girls' School.
Last month Jack was in Los Angeles, in the United States, to look for a tennis academy where he hopes to study in future. "I played some local tournaments and won three doubles and three singles titles," he says. "The standard of players at the tournament was not high, but playing in consecutive tournaments helped me to boost my fitness."