The snow as I write in Germany is falling gently to the ground outside, softly and silently covering the valley of the Rhine with a gentle, pristine whiteness.
As always, there is something almost eerie about this transformation, an aura of surreal otherworldliness.
The German forecasters tell us, however, that the snow will all be gone within a day or two, and that the Christmas will be green, not white. This apparently is not uncommon. About 30 per cent of Christmases are white in this part of Germany, but in the other 70 per cent of cases, there is nearly always snow before Christmas, followed by a relatively mild spell which extends over the festive period. In Ireland, on the other hand, few of us have ever really seen a white Christmas. Ireland experiences very little snow compared to most European countries, and when snow does occur, it is much more likely to arrive in January or February than in December. But the frequency of white Christmases depends to a large extent on which criteria you care to choose.
For example, the average number of days in December on which snow falls varies from about six in the north to a mere one in the south, which suggests, prima facie, a chance of somewhere between one in five and one in 31.
The statistics however are misleading: a single flake is sufficient for meteorological purposes to constitute a "day with snow" - and may be enough, indeed, to win a bet if it should fall at a designated spot within the 24 hours of Christmas Day - but it is a far cry from the image conjured up by the immortal crooning of Bing Crosby.
Perhaps we should think in terms of the number of December days when snow is already on the ground - rather than those on which it actually falls?
Snow on the ground, however, is even rarer than falling snow: there is snow on the ground in December, on average, on only one day every two or three years in most parts of the Ireland, although on high ground this frequency increases quite significantly.
All in all, there have been only 12 Christmases since 1960 when snow fell in Ireland, and on only five of these - 1962, 1964, 1970, 1980 and 1984 - could the snow have been described as being widespread.
The nearest we have come to a real white Christmas was nearly 40 years ago in 1962, when the snow started on Christmas Day and continued on and off in many parts of the country until New Year's Eve.