Winter
Astronomical and other calendar-based reckoning
In the Northern Hemisphere, some authorities define the period of winter based on astronomical fixed points (i.e. based solely on the position of the Earth in its orbit around the Sun), regardless of weather conditions. In one version of this definition, winter begins at the winter solstice and ends at the vernal equinox. These dates are somewhat later than those used to define the beginning and end of the meteorological winter – usually considered to span the entirety of December, January, and February in the Northern Hemisphere and June, July, and August in the Southern.
Winter-8