There are a few things on your rod that could be affected by prolonged exposure to extreme temperatures:

The varnish could soften enough to stick to the bag
The glue used to adhere the ferrules and reel seat could expand/contract enough that they come loose
If the rod w/bag fits tight in the rod tube, heat can cause a set to develope, particularly where the tips rest against the grip

All of these problems can be fixed, but you could easily avoid them by just taking the rod with you when you go inside.

Regards,
Joe Martin