Overview
- Mexico’s National Meteorological Service and UNAM confirm the solstice instant on December 21 at 9:03 a.m. Central Time, which sets the start of astronomical winter.
- Argentina’s Naval Hydrography Service reports the start of austral summer today at 3:03 p.m. local time.
- Daylight is at its annual minimum and varies by latitude, with Mexico seeing under 11 hours of light and Madrid recording about 9 hours 17 minutes.
- Astronomical winter in the north runs through March 20, 2026, distinct from meteorological winter that spans December through February.
- Seasonal sky highlights include the Ursids around December 22, the Quadrantids near January 3, full moons on January 3, February 1, and March 3, a total lunar eclipse on February 3 and an annular solar eclipse on February 17, plus Earth’s perihelion on January 3.