The first day of winter varies depending on the definition used: astronomically, it begins with the winter solstice on December 21, 2025, in the Northern Hemisphere, while meteorologically, it starts on December 1. Both dates are widely recognized, but the specific start date depends on whether you follow astronomical or meteorological calendars.
According to the Old Farmer's Almanac, the first day of winter in 2025 is Saturday, December 21, which coincides with the winter solstice—the shortest day and longest night of the year in the Northern Hemisphere, occurring around December 21 or 22 each year [1]. This astronomical definition marks winter's start based on Earth's position relative to the Sun. Conversely, the meteorological calendar, used by organizations like the UK Met Office, defines winter as beginning on December 1 and ending on February 28 or 29 in a leap year [2]. Additionally, the Old Farmer's Almanac also recognizes December 1 as the start of winter based on the astronomical calendar, aligning with the seasonal change in the sky [3]. In summary, the precise start date of winter depends on the context: December 21 for astronomical purposes and December 1 for meteorological purposes. Many European countries historically recognized winter starting around late November or early December, but the most common modern distinctions are as described [4].