A man with a thermometer in his mouth under a thundercloud

Under the weather

Meaning: Feeling sick

Originated in: 🏴‍☠️ International Waters

Earliest attestation: Observations on Colonel Taylor's Letter by R. Peters (March 15th, 1809)

Under the weather is an old nautical term meaning to feel ill. It is believed that it derives from the fact that when a sailor was feeling sick, whether by sea or germ, he would be sent below deck to rest. This would keep him out of the elements, out of the way, and reduce the amount of rocking felt. If someone was under the bow or the rail of the ship on the side from which the wind was blowing (the weather side of the ship), he would said to be “under the weather bow” or “under the weather rail”, respectively. It is believed that these just got shortened to “under the weather”, although there is no actual written evidence of this.

Before long, this idiom was adapted by us landlubbers as well, and today few even know of its nautical origin. Early on it actually gained a second meaning of just generally being down on your luck and facing adverse circumstances. An early example of this is the 1853 book The Old Sea Captain, where the titular character implores others to share their goods with those “under the weather” as God says we should. However this form of the phrase is no longer used, and today it solely means feeling sick.