My personal experience: In 1995 I put my clubs away after the season in a corner of an enclosed, unheated screen porch attached to the back of my garage. Soon after, I got downsized and began working 70-hour workweeks as a self-employed “free man”. The clubs stayed there until my retirement and return to golf in 2007. Temps ranged from the 90’s in the summer to periods of below-zero (f) in the winter.
Those years in storage had the following effects:
The bag was about 30% covered in a thin mildew/mold. Took a little scrubbing to clean up. Ended up replacing the bag mid-season due to developing cracks and minor rips.
The grips weathered pretty well, but I did replace them
The steel shafts showed small patches of surface rust, quickly dispatched with an SOS pad. Cleaned up like new.
The graphite shafts showed no ill effects and wiped clean with a damp cloth. I’m still hitting one of them four seasons later.
While not optimal, I don’t see (or have) a problem with “cold storage”. Heck, I doubt anyone here has kept a set of clubs for as long as mine were stored.
You might want to make room inside for your balls and shoes.
I still have a dozen “new” Top Flites that were in that bag when I first put it away. Afraid to hit ‘em…