What Is a Rainfly?

A rainfly is the floorless, waterproof outer layer of a double-wall tent. (The inner layer, usually with lots of mesh to keep the bugs out, is known as the tent body.) If you have a single-wall tent, you're essentially dealing with just a rainfly that has a floor on it.

Although you might expect a rainfly to be an impervious layer between you and the world, on decent to high-quality tents the fly will have at least one vent with a little hood on top to shed precipitation. This helps cut down on the wetness and potential misery of condensation inside the tent.

A rainfly should be pitched as taut as possible; this allows it to more easily shed wind, rain and snow. If the inner wall of a double-wall tent touches the rainfly, either the tent is poorly constructed or there's something wrong with your pitch. And if your tent is narrow enough that you brush up against the inside of the fly during normal activities, you need a wider tent -- touching the fly allows moisture to seep through from outside.

Most car camping tents have a rainfly too, but it might only cover the very top of the tent or extend partway down the sides. That's not enough coverage to protect you if the weather turns bad -- so if you're taking your tent backpacking, make sure the fly extends all the way down to the ground.

Some double-wall tents allow you to pitch the rainfly separately from the tent body, basically turning your tent into a tarp supported by poles. This is a great way to cut down on tent weight, but you usually need a footprint (which adds a few ounces of weight back in) to complete the pitch. Oh, and watch out for bugs!

Finally: On almost all double-wall tents, one edge of the rainfly contains some extra fabric that forms a ​gear vestibule.

Also Known As: flysheet, outer tent, fly

Alternate Spellings: rain fly