The 2018–19 North American winter refers to winter as it occurred across the continent from late 2018 through early 2019. While there is no well-agreed-upon date used to indicate the start of winter in the Northern Hemisphere, there are two definitions of winter which may be used. Based on the astronomical definition, winter begins at the winter solstice, which in 2018 occurred late on December 21, and ends at the March equinox, which in 2019 occurred on March 20. Based on the meteorological definition, the first day of winter is December 1 and the last day February 28. Both definitions involve a period of approximately three months, with some variability.