Back in the October snow that caused power outages for up to a week and more, they said houses were down in the 40s, that was with night temps in the 20s so I imagine they'd go lower than that with these temps.
Problem is we're not used to it, some years this cold wouldn't bother me, today it's chilling me to the bone. Gonna stay inside tonight by the wood stove.
When I was in Grammar school every time it cold like this the old boiler would break down and they would send us home, I had more days off for cold than snow back then.