40° and 14° are quite different. I doubt any enclosed garage in Reno ever sees 14°. Even at the lake, that would be unusual.
Cool dark, bagged and away from motors (ozone source) appears to be the standard. Stacked if mounted, vertical if unmounted(This is not really clear...). Basements are probably best if you have one as long as it is dry.
http://www.dunloptires.com/care/storage.html
http://www.yokohamatire.com/pdf/tsb-112102.pdf
http://www.tirerack.com/tires/tirete....jsp?techid=37