How long to wait between usage and charging of a LiPo (or Li-Ion)
High or low charges on a stored lithium battery stress it, even with the battery otherwise idle.  The best way to store lithium-ion or lipo is at about half charge and close to 0C (32F) without actually freezing it.  Note that there's a lot of superstition about batteries, and you'll get different answers from different places, so don't be afraid to verify.

Also:


Charge only at room temperature 
Use at room temperature or slightly below 
You'll get a lot more charge cycles if you keep it between 20-80% charge.


http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries is a good detailed source.