there is a danger of pulling rain water too aside of cool air from the window/s since the fans are giving them extra push.
It's a risk, up to you to assess how small or large. GFCI the circuit that serves the room, maybe.
DO PUT A GFCI (either a replace-the-outlet type or replace the breaker in the panel doesn't matter which) on any circuit that serves a fan in a window.
However, if the window is on the "normally downwind" side of your home, the screen should keep any water from entering your home that way.
Having both intake AND exhaust fans is generally redundant - IMO go all one or all the other, don't mix-and-match or you're wasting electricity for little or no return.
Pushing or pulling air in the same direction as it's natural flow (either through heat rise or wind pass through) works better than trying to fight the natural flow.
To Citronick:
I like the Gigabyte 2 fan model 1070s
https://www.newegg.com/Product/Product.aspx?Item=N82E16814125875 which are fairly often on sale for about as low as any other 1070 model but seem to clock as high as any of them.
Their ITX 1070 model
https://www.newegg.com/Product/Product.aspx?Item=N82E16814125893 isn't quite as fast, but works VERY nicely in the "outside" slot of my 3-card rigs for heat management on the middle card as it's only about 7" long and leaves one fan on the middle card completely clear.