What is the first day of winter?
Astronomical winter in the northern hemisphere begins at the December solstice, the shortest day of the year and the point where daylight starts lengthening again. The instant falls on 21 or 22 December depending on the year, so this countdown uses 21 December as an approximation. Meteorological winter starts on 1 December. The earliest sunset and the latest sunrise do not happen on the solstice itself, which is why evenings begin drawing out before the mornings do.
The next one falls on Monday, 21 December 2026, and this page counts down to the midnight that starts it in whatever time zone your browser reports. For a date of your own, the deadline countdown takes any target and tracks progress against it.