A zephyr is the gentlest breath of wind. I'd more use it when becalmed and you feel that very first stirring of breeze: a zephyr! (For pop culture, in Master and Commander then the jinxed midshipman’s funeral is over the first breeze starts breaking their being becalmed).
I'm a bit surprised its not a common word. I'm Australian and know it well.
In sailing I would more use the word 'Gust' as thats what we're looking for across the water. A darker patch of water that shows where a bit of wind is. So a dinghy sailor will always be looking for the gusts. On Olympic coach will be driving it into the crews. I saw one kid in an Optimist the other day with a coaches speed boat beside him yelling "Gust" at each gust. Because the Optimists are small the "gusts' were coming about every 10 seconds "Gust, Gust Gust" the poor kid was being hassled no end.
When I was racing on flat water, harbours etc we called them Puffs, or Darkies... the gust making the water darker. I don't think they use 'darkies' now, but it was never meant to be racist.
When becalmed we would call up Hughie for a gust. "Come on Hughie, give us a puff". Dunno who Hughie was!
We never called them cats Paws, but knew of the phrase.
Ahhhh to sit under a palm tree with an icy beer and a zephyr of cool breeze