For example, under the weather is an idiom meaning ill. So when people say "I'm under the weather", they are saying that they're not feeling well.

例如，“under the weather” 这个习语的意思是“生病了”。所以当人们说 “I'm under the weather” 时，他们是在说他们感觉不舒服。

youdao

We must stress the importance of listening to our emotions and not the guesses as we often do: "I'm sad, it must be because of this lousy weather.

必须强调的一点就是要聆听情绪，而不是我们通常的做法：只是猜测，比如“我很伤心，肯定是因为这讨厌的天气”。

youdao

I'm not going to worry about the weather this weekend.

我就不用担心这个周末的天气了。

youdao

"It's not as busy, not as packed as I'd imagined but the weather's alright and I'm enjoying it, " he said.

BBC: Carnival costumes