I just got home with a Betta. I am temporarily using a small (about a gallon) glass container for him. I plan on getting a much better setup (with heater, filter, etc.) soon. I would have waited until I had this to bring the fish home, but I figured anything is better than the tiny cups they are kept in at Petco.
Now that I have the Betta (in it's cup from Petco) and my container setup (I did, at least, condition the water):
How long should I wait for the water in both containers to reach room temperature, so that I can safely put the Betta in it's new container?