You're lucky. Our hummingbirds left early this year in Sept. I miss them badly.

My mother had Anna's stay all winter long last year in the Pacific NW. This year I have noticed 3 Anna's still here, and right now the temps are at -6F degrees with the windchill. I am rotating 4 feeders, two in to thaw and two out for the hummers. I sure hope they'll be ok during this cold blast. I love still having them around, though!

I live in the Puget Sound region and the last few years the Anna's have overwintered here, so I keep my feeder out all year. What I do (and I try to post this everywhere I see people talking about feeding in below freezing weather) is wrap my feeder in little white Christmas lights (not the LED, but the incandescent). They give off just enough heat to keep the feeders thawed. If it's super cold, just wrap more lights. It doesn't seem to bother the birds and looks very festive at night.

I actually hang something below the feeder to hold some of the lights below it, too, so the heat rises up and keeps it warm enough to not freeze.