Iranian people celebrate the night of the Northern Hemisphere's winter solstice as, "Yalda night", which is known to be the "longest and darkest night of the year". · So far as what most folks actually experience, early December is the darkest time of the year. For example, in Boston, the Sun started setting at 4:13 PM on December 3 and won’t start setting later, at 4:14 PM, until December 15. · When is the Winter Solstice? The "darkest" day of 2025 explained. On Sunday, Dec. 21, at exactly 10:03 a.m. EST, the Northern Hemisphere's astronomical winter officially begins with the winter... · The winter solstice is the darkest day of the year and the beginning of astronomical winter. Find out what really happens to the Sun, how our ancestors understood it, and why this moment is important today. · During the winter solstice, the Northern Hemisphere is tilted farthest away from the Sun, causing sunlight to spread over a larger area and deliver less warmth and light. As a result, the Sun follows its shortest path across the sky, making this the darkest day of the year. · The winter solstice is when the sun makes its shortest, lowest arc. The good news for sun lovers: It then starts climbing again and days will get a little longer every day until late June. Meteorological and other seasons definitions Days Get Longer During Winter Astronomical winter begins at the winter solstice, which is the shortest day of the year. This means days get longer during winter—very slowly at first, but at ever-larger daily intervals as the March equinox approaches, heralding the start of spring.
