The very moment of winter solstice on 21 of December, 2024,  the darkest hour –  when the Sun reached its southmost declination – has occurred at 11.20 EET (Finnish time, among others). This is not a fixed moment in time, instead, it is calculated taking into account nonuniformity of the Earts’ motion. So congrats, we have overcame the darkness,  and living already more than 24 hours on the rise!

In this article from Sky&Telescope the mechanics of the winter solstice are explained: