Flying in rain might get you a free rinse but it can also affect your airplane’s performance in a variety of ways.

By Dave Higdon

To my mind, only a couple of decent reasons exist to fly through rain: First, because your destination is out there in or beyond the precip—and it’s light rain and not far through it, at that; second, because you’re too cheap or lazy to wash the plane normally. Otherwise, rain stands among those conditions to not take lightly—and on many fronts, to be taken as a condition to avoid as much as possible.

When you think about it systematically, a lot goes on with the airplane when exposed to rain and—aside from the possibility of improved cooling on a hot day—it’s difficult to conjure up much to commend rain flying to…