The full coverage fly also drops the water off a little away from the tent, which somewhat inhibits it from running or wicking back under the tent. Full coverage usually costs a few onces in weight. If you are using a partial fly tent, use caution not to have anything touching the single wall. Felt wide-rimmed hat. You wouldn't think a cloth hat would keep you dry, but it does.
Water is wicked to the edge of the rim, where it falls off.
Vents are a feature to look for. They allow body moisture to escape during warm weather and when high humidity would otherwise trap it. Rain will run around grommetted vents and off. Gore-tex lined hats provide moisture protection and some degree of breathability even without vents. He used a small umbrella.