Chances of a White Christmas in Europe: Declining Snow Cover Trends on Christmas Eve

For many, the magical feeling of Christmas is not complete without a blanket of snow. But how common is a snowy Christmas in Europe? In this article, we dive into the likelihood of experiencing a white Christmas in different regions of Europe. We’ll also examine trends: is the chance of a snowy Christmas Eve on the decline? If you’re wondering where to go for the highest probability of a white Christmas, or you’re just curious about how these odds are changing in your area, this article is for you.

Check the white Christmas probability in US here.

All data and content are provided by the author, ensuring content quality and accuracy. While the text is written by the author, AI tools have been used to refine some sentences. All content is thoroughly checked by the author. Website’s terms and conditions apply.

We used ERA5 reanalysis data to explore the probability of a white Christmas. Since the main Christmas celebration for many European countries takes place on Christmas Eve (24th of December), we focused on whether there’s a snow cover on this day at 18 UTC. This corresponds to 18:00 local time in places like Iceland, the UK, and Portugal, 19:00 in most of Western and Central Europe, and 20:00 in regions like Finland and Eastern Europe. The choice of this specific time is in line with the widespread tradition of evening celebrations on the 24th. It’s however worth noting some countries have different customs. If you’re interested in details of the methodologies behind our findings and what reanalysis data is, you can find more about this at the end of this article.

Probability of a white Christmas in Europe

In our current climatological period (1991-2020 average), a snow cover on Christmas eve is more or less guaranteed in much of Lapland, the Scandinavian highlands, the elevated regions in Iceland, the higher peaks of the Alps and Pyrenees and even the highest peaks in the Balkan countries and Turkey, as indicated by the purple colors in the figure below.

As a general rule, the further you move towards Europe’s southwestern coast, the slimmer the chance of a white Christmas. However, local effects – especially elevation (in hilly and mountainous areas) – can somewhat compensate for this and increase the odds of snow on Christmas eve.

Change in snow probability on Christmas Eve in Europe

If we go back in time, to an earlier climatological period (1951-1980), we see that Christmas Eves in Europe were (much) more likely to be snowy. Back then, a blanket of snow was almost a certainty across most of Scandinavia, Finland, and parts of the Baltic States, Belarus, and Eastern Europe’s mountainous regions. In the Alps, the elevation for guaranteed snow on December 24th was much lower, making a white Christmas a more common occurrence in more places. The same goes for the Pyrenees.

In Germany, the chances of snow ranged significantly (from 25-70%, with even higher probabilities in mountainous regions) but were much higher than is the case nowadays. Most of Eastern Europe used to have a 60-90% likelihood of experiencing a snow cover on Christmas Eve.

Snow in Europe on Christmas Eve much less likely

When comparing snow probabilities between the two aforementioned climatological periods, one thing becomes especially clear: in our current climatological period, the likelihood of a white Christmas has dropped substantially across most of Europe. This decline stretches from Spain to Eastern Europe, and from Finland down to the Mediterranean.

The most pronounced decreases in snow probability are found in Eastern and Central Europe, particularly in areas like Germany, Poland, the Balkan region, parts of the Alps, and Southern Sweden. Here, we’re witnessing enormous drops, ranging from 20 to 40 percentage points (%pt), and in some localities, the drop is as steep as 50%pt. Regionally, in places such as the lower parts of the Alps, southern Germany, Massif Central, the Balkan and small areas in Poland even show a decrease of more than 50%pt.

Yet, white Christmas odds are not decreasing everywhere; a few regions actually show a slight increase in the likelihood of snow compared to the past.

A percentage point is a unit of measurement used to express differences in percentages. E.g. moving up from 40 percent to 44 percent is an increase of 4 percentage points (although it is a 10-percent increase in the quantity being measured).

Higher likelihood of white Christmas in the UK?

In some areas of Europe, including parts of the UK, our analysis indicates a subtle increase in white Christmases. However, this increase must be understood in the context of historical rarity. In regions where snowy Christmases have historically been rare, even a small number of snowy events in more recent years can disproportionately influence the overall trend. This is a classic example of a low signal-to-noise ratio, where weather variability plays a large role.

A case in point is the UK, where several snowy Christmases in relatively recent years, for example around the turn of the millennium and in the early 2010s, have contributed to this increased white Christmas probability.

Also around the Black Sea, there is a notable uptick in the likelihood of a white Christmas in a few areas. Yet, these instances might be more of an anomaly rather than an emerging pattern and an uptick in the most recent climatological period does not mean that these places will continue to see upward trends in a further warming climate.

In contrast, the far north of Europe and the high Alps show no significant change in snow probability; here, a snowy Christmas Eve remains almost certain. Despite regional warming, the winter temperatures in these areas are still predominantly below freezing. The result is that precipitation falls (mainly) as snow and existing snow covers stays intact. In some northern regions, like Lapland, the amount of snowfall has even increased (although there is no significant trend in maximum snow depth). This is attributed to the fact that milder air contains more moisture, resulting in heavier snowfall.

We also don’t see clear changes in for example the Benelux region, which makes sense because the probability of a white Christmas Eve was already very low in the past.

Trends in snow probability on Christmas Eve

The previous map visualized the difference between two climatological periods. And although this might be a decent indicator of a trend, this difference in snow probability between two climatological periods is not exactly the same as a trend, as both these periods can be influenced by yearly weather variations. Therefore, we also computed trend lines in snow probabilities across Europe for each datapoint.

This approach is a more ‘fair’ comparison, although this methods has its own limitations (which are discussed in the methodology section at the end of this article).

When we look at the snow probability trend from 1970 to 2022 in the figure below, we see that the decrease in white Christmas probability is even more pronounced in many areas. Extending our view back to 1950 intensifies this trend, with positive trends almost completely disappearing. However, there remains a slight positive trend in southern Great Britain. This suggests that while most of Europe is experiencing a decline in the likelihood of a white Christmas, snow on Christmas has indeed become (slightly) more likely in southern Great Britain over the past decades. Again: it is not necessarily likely that this slightly upward trend will continue in a climate that continues to warm.

To conclude: where will it be a white Christmas in Europe?

The results discussed in this article can be helpful for someone looking to experience a white Christmas in Europe. If you’re looking to find snow on Christmas Eve, far northern regions and the highest mountain ranges are your best bets. As a general rule, the further northeast you travel in Europe, the higher your chances of a snow cover existing on Christmas Eve. Still, it’s important to keep in mind that snow cover probabilities on Christmas Eve have been declining steadily in much of Europe over recent decades. There are a few exceptions, such as southern England, where we’ve seen a small uptick in white Christmases in recent decades. In the future, as Europe will continue to warm, white Christmases will probably become increasingly rare across most of the continent.

Check the white Christmas probability in US here.

Methods:

The ‘Snow Depth’ variable from the ERA5 dataset was used for this analysis. ERA5 is a reanalysis dataset from the European Centre for Medium-Range Weather Forecasts (ECMWF). Reanalysis is a technique combining past observations with modern forecast models to recreate the historical state of the atmosphere.

We downloaded the snow depth variable for the 24^th of December at 18 UTC for all years of interest. The original unit of the data is water equivalent (m). This number was multiplied by 100 (to convert to cm) and consequently multiplied by 10 (assuming a snow water ratio of 10). If for a certain grid cell (datapoint) the snow depth at the 24^th of December, 18 UTC, was at least 1 cm, we classified it as a ‘white Christmas’. Note that in some countries, official definitions of ‘white Christmas’ might differ. For example, in The Netherlands, a snow cover must be present at both the 25^th and 26^th of December, in order to qualify as a ‘white Christmas’, because these are the dates that Christmas is celebrated in this country.

The trends in each grid cell are determined by applying a linear fit on binary snow depth data. The binary snow depth represents the presence (if snow cover > 1 cm, binary value 1 is given) or absence of snow (if snow cover is < 1, binary value 0 is given). While linear fits are generally better suited for continuous data and logistic regression might be more appropriate for binary data, the linear fit method was chosen for simplicity and computational efficiency. This approach still offers a decent overall view of the snow cover trends, and can indicate general increases, decreases, or stability over time, though it is less precise in estimating exact probabilities or changes.