Winter Solstice 2025: Why December 21 Marks the Shortest Day and Longest Night of the Year? Explained

The winter solstice, also known as “the longest night,” falls on December 21, 2025. It is the time of year when the Northern Hemisphere is experiencing its longest night and shortest day at the same time. It also marks the beginning of the astronomical winter (Meteorological winter began on December 1) and is a time of celebrating the winter solstice.

What is the winter solstice? 

During the winter solstice, the North Pole of the Earth is tilted away from the Sun by approximately 23.5 degrees. As a result, the Sun is directly above the Tropic of Capricorn at its maximum altitude. Due to this extreme tilt, the Sun does not rise high, and thus the daylight is shorter; consequently, the areas north of the equator are experiencing the minimum daylight of the calendar year.

Exact Time in 2025

In 2025, the solstice will take place on Sunday, December 21, at 10:03 a.m. Eastern Standard Time, which is equal to 3:03 p.m. UTC and nearly 8:33 p.m. Indian Standard Time. Even though people informally refer to it as “solstice day,” from an astronomical point of view, it is one single moment when the Sun’s apparent southward motion halts (“solstice” in Latin means “sun stands still”) before it begins to move northward again. Daylight in the Northern Hemisphere will gradually increase from tomorrow onwards.

Why It Matters

The solstice does not result in the coldest day as such; temperatures tend to be lower due to the delay of land and oceans in losing heat. However, the event is celebrated by many cultures as being the darkest night, which heralds the arrival of light, and they have festivals of renewal and hope. For astronomers, the Sun’s low position at midday creates very long shadows, and in high-latitude areas, there are communities that have only a few hours of very dim sunlight or even polar darkness, when the Sun never goes above the horizon.