A。
根据答语Its cloudy．"多云"可推知上文询问天气状况，其英文表达有两种，Whats the weather like…？；Hows the weather…？结合题干…the weather in Hangzhou？故填Hows，故选A用 Hows
Hows the weather in Hangzhou? 杭州的天气如何?
若用 What 要改写为 Whats the weather like in Hangzhou?是Hows
Hows the weather?
Whats the weather like?