I’ve heard of this for frost prevention, but never rain. Do you know of a specific vineyard doing this?

Napa and Sonoma vineyards have been doing it for decades: https://www.sfgate.com/business/article/vintners-rush-to-dry... (dated 1997)

It’s pretty rare though. They usually only do it when it rains heavily right before harvest.

parent comment said “every time it rains”… this article and your comment make it sound “pretty rare”.

I could certainly be wrong about the timing. I’m definitely not a grape growing expert by any means, I mostly know about it from being in the UAV world and having had some discussions about replacing the helicopters with drones for getting the water off.

having worked at a cargo drone company, that is one thing that our platform would have excelled at. although ours had a tendency to simply flatten vegetation when "cornering" at low altitude.

Yep. I recently visited some high end vineyards in Arizona, and the grapes really thrive because of how dry it is. They are able to irrigate carefully to avoid wetting the tops of the plants.