Hi Eric,
Thanks for your quick response. I can't post a picture at the moment, but am certain it's a gray tree frog as it looks just like the pictures on our state's DNR website.

I did see the information about temperatures it can withstand on the care sheet, but we're having daytime highs of 20 degrees and lows of 5-10 right now.

I'm much more interested in letting it hibernate than caring for it until spring, though I appreciate your suggestions if I have to go that route.
Julie