Many cities across the country issued the year's first hot weather alerts on Tuesday, but a government weather expert said the heat wave won't stay for long.

The mercury hit 37 C in downtown Shanghai, where an orange alert was issued for the first time this year along with a warning to citizens - especially children, the elderly and the sick - to keep cool and avoid too much time outdoors. Other areas in the city also reported a high of over 35 C.

Heat wave forecast to be brief

Similar temperatures were reported in other cities in the Yangtze River Delta region, as well as in Beijing and Wuhan, capital of Hubei province.