Was thinking about storing a few speakers over my garage. Problem is ...

The temperatures up there run from -10 to 130+ deg F (-20 to 55+ degC)
I know I'd be pushing the storage specs on the x-over components but I'm also hesitant about the drivers and cabinets. Anyway thought I get a discussion going on it ...

Note: no active or powered speakers would be stored

I"d be a little worried about it here in Iowa as we probably exceed your temp swing.

Not sure if the adhesives used for the surrounds and coils can withstand sustained low temperatures.

Then there's the ferrofluid for the tweeters. Depending on the compound, it may expand and there may not be enough room to accommodate the expansion.

Axiom has an environmental chamber but I'm not sure if they've characterized long term, low temp performance.

Speakers are pretty resilient to being stored at high or low temperatures. I don't see any problem with your storage area. If you try to play them at really low temperatures the tweeter will be way down until the Ferrofluid warms up.