The Independent says it is tomorrow - here's why: (note earth orbit is 365.25 days not as written below - leap year every 4 years)
Britons are set to breathe a collective sigh of relief as the country welcomes the shortest day of the year - before the days start getting longer and brighter.
Winter solstice 2015 will fall on 22 December, when the sun's daily maximum height in the sky is at its lowest, and the North Pole is tilted furthest away from the sun.
The solstice is usually on 21 December, but comes a day later this year for the same reason we have leap years - the Earth’s orbit takes 365.5 days, so each year the solstice is pushed back by another six hours.
This year, the solstice will occur in London at 4.49am, with sunrise expected at 8:04am. The sun will set at 15:54, which means there will only be just under eight hours of daylight on 22 December.