I wouldn't be worried about being cold outside... if you are you may not have cooked with a WFO, if it's 30F outside you'll likely be comfy with warm boots on and a bathing suit...

Seriously though, don't want water inside and freezing. When you consider the oven will easily get to 1000F when fired the 50-80 difference in outside temp from summer to winter is something only the human body notices, the pie will cook just fine if it's 50 degrees cooler...