It's a little more cold than usual for this time of year in San Diego, or for any time of year in this city. I don't remember ever experiencing weeks of low-50s temperatures in my adult life. If you laugh and think this isn't that low, then consider that in San Diego we don't own any proper winter coats or thick jackets, and our houses are usually over 50 years old with zero insulation. We have no chimneys, generally, and so we rely on electric heaters to do whatever they can. Poor insulation in 45 degrees feels like sitting in the shade on a cold day. The house does nothing to keep you warm.