Right now the external thermometers are reading a balmy 13* Fahrenheit here at Casa de Tam. You can't actually see your breath in the corners of the house farthest from the propane heater, but it feels like you could. I moved a small electric heater into bathroom just in case; nobody likes burst pipes. The CFLs in the overhead light fixture don't generate much waste heat; I'll admit to leaving a floor lamp with three big halogens running all night to take the edge off the cold in the corner near VFTP Command Central.
Pretty ice fog all along the lake though; it's left the bushes and trees all glittering with a coating of fairy frost.