I'm no expert/authority, but from my experience:
High heat may affect some glues and paints. Epoxies and cyanoacrylates are generally not a problem, but aliphatic resins ("white" and "yellow" glue) can be.
Some older forms of "BlueTube" and similar airframe materials were known to swell in high heat. This has not seemed to be a problem with the later generation stuff.
If you tend to use masking tape or something similar to tighten airframe/nose cone fits and such, don't leave it on when you store at high temps - it will get sticky and gooey.
There is little to worry about with just temperature extremes - the real thing to be concerned with is temperature extremes coupled with humidity problems. Just cold will likely not harm anything, but cold and wet can cause all kinds of problems. Same goes for higher temps along with high humidity. As long as your shed is dry, and your rockets are stored dry, I doubt you will see any problems.
For what it's worth I also deal with extreme temperature shifts. All my stuff also stays outside here in the southwest desert, and in the winter it is often below zero during the night at least. During the summer, it's common for temps to be WELL above 100 degrees. And as anyone can tell you who goes to the Hellfire launches - it gets HOT out there on the salt flats in July and August. I've never had any problems due to high or low temps, and my fleet consists of everything from paper & balsa rockets built with Titebond, to BlueTube and AC ply built with hobby grade epoxies, to carbon and fibreglass built with high-grade epoxies. I also store all my propellant/igniters/etc. outside. And those temperature extremes have not been a problem.
Now, ask me about trying to PAINT & finish during the winter when I have no indoor facilities (like I'm trying to do right now), and I can give you all kinds of horror stories.
s6
