When you hear Christmas is around we are rest assure that the winter has arrived and the weather is quite chilly. In many parts of the world it is snowing and these places look as if it is wrapped with a white carpet. This occurs mostly on Christmas Eve. The countries which experience white Christmas are mostly in the northern hemisphere since during December southern hemisphere goes through summer.
Even White Christmas is a famous song sung by Bing Crosby from the film Holiday Inn which states about the beauty of traditional Christmas Eve. This term traditionally means that the place is covered with snow almost of a thickness of 1cm to 2 cm. On Christmas if it snows then the met offices declares it as a White Christmas.
White Christmas is mostly seen in United States. In Canada most places have white Christmas round the year. United Kingdom used to have white Christmas very long ago around 1550 to 1850. That has become a history. But in 2009 some parts of Britain had experienced white Christmas. Roads were quite badly affected. It was one of its kinds for the first time since 2004. Ireland is a country with a cold and wet climate and hence white Christmas arrives there bit late. It occurs there in the month of January and February. Statistics say that once in every five and a half years white Christmas occurs at Dublin airport. Last it occurred in 2004. Poland is seeing white Christmas rarely nowadays. The northeastern cities sometimes experience white Christmas but the frequency has lessened. Krakow has last experienced white Christmas in 2010.
If we consider the southern hemisphere it is quite next to impossible to have a white Christmas there since they experience summer there. But here too are some exceptions. Except in Antarctica since there is snow round the year and it is uninhabited. Southern Alps of New Zealand can experience white Christmas since here it is snowing round the year.
Technically speaking, it has stricter definition though. In the United States, the official definition of a white Christmas is that there has to be a snow depth of at least 2.5 cm at 7:00 a.m. local time on Christmas morning. In Canada the snow has be has to be more than 2 cm on the ground on Christmas Day.