The winter solstice, also called the hiemal solstice or hibernal solstice, occurs when either of Earth's poles reaches its maximum tilt away from the Sun. This happens twice yearly, once in each hemisphere.

What day has the most light?

In the Northern Hemisphere, “peak” sunlight usually occurs on June 20, 21, or 22 of any given year. That's the summer solstice. By contrast, the Southern Hemisphere reaches peak sunlight on December 21, 22, or 23 and the Northern hits peak darkness — that's our winter solstice.

Why is June 21 the shortest day of the year?

On the June solstice, it reaches its northernmost point and the Earth's North Pole tilts directly towards the sun, at about 23.4 degrees. It's also known as the northern solstice because it occurs when the sun is directly over the Tropic of Cancer in the Northern Hemisphere.