In the wintertime, the biggest electricity demand is heat. When temps get down to 30-40F, there's little differential between that and an interior temperature of 63-68 degrees. It's easier to heat a place with a heat differential that small. But when it gets colder, it takes longer to heat to that temperature range.
Many homes are still heat-inefficient; I see many roofs here clear of snow because of heat loss, be they roofs of stick-homes or mobiles...mostly mobiles. Inefficient insulation, cracks & gaps in doors & windows, floors with low to no insulation all lead to higher power usage, especially in sub-freezing temperatures. The place I was in for 3 months? 60YO single-wide, thin walls, obviously aged insulation, single-pane windows, aluminum doors, soggy ceiling insulation due to a roof perforated in many areas (
also leaking)...and zero flooring insulation. Add holes in the skirting...there ya go. The current place I'm at: also a mobile, thermostat set to 62. The furnace ran all night because of the temperature differential between 5 degrees outside and 62 inside. At freezing or above, the furnace cycles normally...it just got too cold outside and the heat was bleeding out.
There's a lot of substandard housing here, not sure about your locality. Oh...and there are many people out there who have their interiors cranked to 70 and above out there, too. 61 plus warmer clothing works here at my place.
Are you in a metropolitan area? That can strain a grid pretty hard. I'm rural, the only dangers here are lines snapping from ice weight or transformers blowing...or when a numbskull in a 4x4 with no sense of safety kayoes a pole.