Some blame can also be apportioned to global warming: thirteen of the fifteen hottest years on record (since the start of record-keeping in 1880) have been since 2000, with 2015 being the hottest year ever recorded. Even though summers are getting hotter, driving up air-conditioner usage nationwide, there have also been some spectacular cold snaps as well, the polar vortex in 2014 being among the most memorable in recent times.
