First Day Of Winter 2025. First, it moves in a big circle around the sun; Winter 2025 starts on sunday, december 21st in the northern hemisphere, with the first day of winter being the shortest daylight day of the year with the earth's axis having reached its furthest tilt away from the sun and begins to change directiion back.
Summer begins with the summer solstice, friday,. Winter solstice 2025 (beginning of astronomical winter) on the day of the winter (december) solstice, the sun passes through the southernmost point of the ecliptic, that is, as far as possible from the celestial equator to the south (for the northern hemisphere of the earth).