Eight
Short story: "Whiteout" is a story about the early western frontier and a fictional event during our calendar adjustment in 1751. When George Washington was nineteen December 31 was followed the next day with March 1st (there was no January or February in 1751). In 1752 they took eleven days out of September and that was our last calendar adjustment. In the 265 years since we have added leap year and the leap second to try to keep the calendar in sync with the sun's rotation.
If you want to know how well we are doing? When close to spring, summer, or winter on the calendar call the National Weather Bureau or local television station weather person and ask for the meteorically date of spring, summer, or winter. My guess is there is about twenty day's difference between the meteorically date and the calendar date? Then ask yourself if the date difference could have anything to do with real or imagined global warming?