Covering a car can often do more damage then just leaving it outside bare in your nice damp area of the NE - especially if the wrong cover is used. Dampness seeping out of the ground - causes condensation then rust. If a cover can't breathe well, and regardless of any advertising hype they don't, then almost any day that it warms up, condensation will form - then rust on steel and corrosion on aluminum parts. Of course there is the ozone effect on tires, wiring and vinyl interiors.

Brake systems will absorb ambient water

To do a test to satisfy yourself, put an 8' x 10' piece of 4 mil plastic on the ground, on your driveway or often even in a garage. Make sure that it is held down. Wait until the sun hits it the next morning - water(condensation).

Yes, people do store cars outside - and covered. I wont