How long does it take for Dejiang to start to heat up?

The summer in Deyang, Sichuan starts to get hot in June. In May, the weather was more comfortable, neither cold nor hot. By mid-June, the temperature increased, the rain increased, and the weather gradually became hotter. By July, the temperature rose straight up. The weather was over 30 degrees, and it felt like it was getting hotter day by day. One day high, in August, the temperature directly reaches around 37 degrees.