对于你的问题可以有多种回答,依次如下:
It is raining in Shanghai.上海在下雨
It's a rainy day in Shanghai.今天上海是雨天
There is rain in Shanghai.上海在下雨
Shanghai is very wet now.上海现在在下雨
最通俗的是第一种说法。如果你想口语话一点会用rainy。最后一种比较美式口语化。
It is raining in Shanghai.
It had a downpour in Shanghai