osuwildlifer, on 23 January 2013 - 11:44, said:
I've always heard that the colder the device, the faster the battery will drain. But I have no real explanation for this or evidence that it's true.
I remember as a kid we put our digimon device out in the sun when it was nearly flat and we thought we were recharging it. It did boost the battery and the screen did turn much darker for a short period of time so yes, temperature does affect the battery.
OP, how about getting a stand/dock for your phone of eBay and put that on your windowsill? Even if your speaker faces the window, the sound will reflect and sound much louder and you don't need to worry about coldness issue. Either way, as everyone else has pointed out, as long as there is no moisture you should be alright.