What is the term for the shortest day of the year in the Northern Hemisphere?

The shortest day of the year in the Northern Hemisphere is the winter solstice.

The winter solstice occurs when the Northern Hemisphere is tilted farthest away from the Sun. The Sun reaches its southernmost apparent position, near the Tropic of Capricorn, producing the year’s least daylight and longest night for locations north of the equator. It usually occurs around December 21, although the exact date can vary between December 20 and 23.

The solstice is an astronomical moment, not necessarily the day with the earliest sunset or latest sunrise. Those times depend on latitude, local geography, and the equation of time, so they can occur several days before or after the solstice.

After the winter solstice, daylight gradually increases in the Northern Hemisphere while the Southern Hemisphere experiences its summer solstice. An equinox is different: it occurs when day and night are approximately equal, while aphelion refers to Earth’s farthest orbital point from the Sun.