What do you think is the difference between the climate in Shanghai, Nanjing and Hangzhou?

I lived in Nanjing for 18 years (Nanjing native) and stayed in Hangzhou for almost 10 years. Personal opinion: When I was in Nanjing, I felt that Nanjing was not alone and the climate was too bad. It's hot in summer and cold in winter. As a result, I came to Hangzhou to study, and it felt like I was back in Nanjing. Alas, the weather in Nanjing is really good. I really had a good time. No blowing, no black.