Winter Solstice, 2021 – Sunset

Griffith Observatory marks the start of winter in the northern hemisphere with a live online talk (weather permitting) focused on the setting Sun. Observatory staff will discuss how the Sun’s changing path across the sky causes seasonal changes and determines where the Sun sets on the western horizon. Learn more about the seasons here.

Winter begins in Earth’s northern hemisphere at 7:59 a.m., PST, on December 21. Summer begins in the southern hemisphere at the same time. The December/winter solstice occurs when the Sun reaches its minimum declination (-23.5 degrees). This is when the northern hemisphere of Earth is tilted as far away from the Sun as possible during the year.

From the autumnal equinox until the start of winter – the winter solstice in December – days become shorter, and the sunset point moves south along the western horizon. This happens because the Earth’s axis is tilted 23½ degrees to its orbit. December 21 is the shortest day of the year.