Car storage in garage?

This is a trivial question but one that I have been wondering. In an attached garage where the temperature extremes may be not more than 90 and no colder than 45 is it best to leave the windows up or down? I figured with them down it allows to car to ventilate, with them up I would think any moisture or anything else would be sealed in. What do you think. The car has full leather interior that might be important. The car spends about 5 day of the week in and only out of the garage on the weekend when it is driven.