NO WAY - Don't use baby powder or other talc at all. It has been thought to be linked to ovarian cancer.
You won't ruin your toy by leaving it unpowdered until after christmas. I have a number of cyberskin, UR3 and now a TPR that requires powdering.
There are many times where I don't worry about powder - because I plan on using it regulary and they are fine. Ya just don't want to let them go permanantly without ever powdering.

It won't melt. If you have really extreme heat and it was hard up again another toy (which the skin ones should never be - they need their own bag!), then it can melt a very slight bit.
But with you being in winter, you won't have a problem!

I just use Summer's Eve feminine powder on mine cause it's made from cornstarch - not talc.
You're much better off just putting it back in the bag or packaging it came in for now. It will be fine until next week. less