China has endured a string of extreme summers in recent years, with heatwaves baking northern regions even as parts of the south have seen catastrophic rain and flooding.
The authorities in the city of 22 million people urged the public to take precautions, with temperatures expected to peak at around 38 degrees Celsius on Monday.
"It's been really hot lately, especially in the past few days," intern Li Weijun told AFP on Monday afternoon.
The 22-year-old said he had stopped wearing formal clothes to work and delayed his daily exercise until after 10 p.m. to stay safe.
"I think it's related to climate change, and maybe also to the damage done to nature," he said.
An orange heat warning – the second-highest in a three-tier system – was issued on Monday as officials encouraged people to limit outdoor activity and drink more fluids to avoid heatstroke.