A gentle pitter patter on your rainfly can be a soothing natural sound when you’re lying down at night in your tent. If those drips start originating inside your tent, though, it becomes a highly unpleasant resting place. And, under the right circumstances, the culprit—condensation—can infiltrate even the most well-engineered shelter.

So, how do you prevent condensation? The answer boils down to three strategies:

1. Pick an optimum place to pitch your tent (answer: under trees)
2. Minimize the sources of additional moisture inside your tent
3. Ventilate, ventilate, ventilate

When warm air contacts a cold surface, condensation can happen. You see this effect in a mug of cold beer on a hot day. The same thing can happen in a tent: Warm air inside moves out to the rainfly, which is cooler because the outside air is cooler. The result is condensation on the underside of your rainfly. That water may then saturate your tent fabric or drip through a mesh window.

Air inside the tent is almost always more humid than the surrounding air, so you want to replace the interior air with the drier outside air. Ventilation strategies include the following:

1. If there’s a gentle breeze, pitch the tent so the door is facing into it.
2. Stake the tent out tautly and tension the fly in order to maximize the airspace between it and the wall of the tent.
3. Open all rainfly doors and rollup sections; only deploy them if rain starts to fall.
4. Open up all rainfly vents, especially opposing ones for cross ventilation.
5. Open up all inner tent windows.

It’s rare for your rainfly to be dry come morning, but if you follow these tips, most of the moisture should stay on the outside—where it belongs.