The exact moment of the winter solstice varies from year to year due to a slight misalignment between the Gregorian calendar and the actual rate of the Earth’s rotation around the sun.

In the Northern Hemisphere, the December solstice is the year’s day of least sunlight, when the sun takes its lowest, shortest path across the sky. North of the Arctic Circle, it is the midpoint ...

The vernal equinox, marking the first day of spring, occurs on Thursday, March 20, 2025, at 5:01 a.m. ET. An equinox happens when the sun's rays are directly over the equator, resulting in ...