The date and time in my 2005 A8L keeps resetting, 0 degree temps here in the great white north, is this a sign for a new battery?

 

Worth checking...they could reset when below minimum voltage and when disconnected. I'd check the voltage with a meter when cold (after resting..no recent running), before starting...should be above 12V and 13.5-14 when running (alternator input). If battery is taxed below minimum when starting, it may reset clock then(?)