when did the uk have a white christmas
White Christmas (weather) In the United Kingdom, white Christmases were more common from the 1550s to the 1850s, during the Little Ice Age; the last frost fair on the River Thames, however, was in the winter of 1813â€“14.[13] The shift from the Julian to the Gregorian calendar in 1752 also slightly reduced the chance of a white Christmas, effectively moving Christmas earlier in the winter.[14] An "official" white Christmas is defined by the Met Office as "one snowflake to be observed falling in the 24 hours of 25 December somewhere in the UK",[14] but formerly the snow had to be observed at the Met Office building in London.[14] By the newer measure, over half of all years have white Christmases, with snow being observed 38 times in the 54 years to 2015.[update][14] A more "traditional" idea of snow-covered ground is less common, however, with only 4 occasions in the 51 years to 2015[update] reporting snow on the ground at 9am at more than 40% of weather stations.[14]