If you say you are under the weather it means feeling slightly ill, or tired, but not really badly sick.
The expression likely comes from sailing. When sailors felt sick, especially during rough seas, they sometimes stayed below deck to recover, meaning they were literally under the weather.
The expression likely comes from sailing. When sailors felt sick, especially during rough seas, they sometimes stayed below deck to recover, meaning they were literally under the weather.
I'm feeling under the weather today.