Definition from Wiktionary, the free dictionary
southwester (plural southwesters)
- A strong wind blowing from the southwest.
- (more often sou'wester) A waterproof hat, often of oilskin, designed to repel wind and rain.
- (more often sou'wester) A long raincoat, often worn at sea.
- (a waterproof hat): cape ann
waterproof hat — see sou'wester