I'll take a rain check. 改天吧。
I'm sorry, but I'll have to take a rain check for dinner this Saturday. Would next weekend work for you?
When it rains, it pours.
I lost my job last week. And someone broke into my house yesterday. When it rains, it pours.
The rain eases off 雨渐小
The rain should ease off in a few minutes. We’d better wait here.
The rain patters on sth.
The rain is pattering gently on the window.
get caught in the rain
I am sorry I am getting caught in the rain and I’m afraid I’ll be late for work this morning.