What are the chances of a White Christmas in Victoria?

It's just one week until Christmas, so the long range forecast is accurate enough to know that the chances for a White Christmas this year in Victoria are virtually nil.  The photo below was taken on the last White Christmas in Victoria, not long ago in 2017.  It won't look like that this year.

So what is the historical likelihood of having a White Christmas in Victoria?  Environment Canada defines a White Christmas as having 2 cm or more of snow on the ground on Christmas morning.  Using that definition, there have been just 6 White Christmases in Victoria since 1914 when the Victoria Gonzales weather station opened: 1937, 1971, 1990, 1996, 2008, and 2017.  So 6 out of the last 106 years have seen snow on the ground on Christmas morning, meaning that over that period there has been a 5.7% chance of having a White Christmas.

Interestingly, the frequency of White Christmases in Victoria has actually increased in recent years.  Prior to 1990, there were just 2 White Christmases in the 76 years from 1914 to 1989 - that's just a 2.6% chance.  But in the last 30 years (1990-2019), there have been 4 White Christmases, resulting in a 13.3% chance.  Amazingly, White Christmases have been have been more than 5 times as frequent in Victoria over the past 30 years than they were in the previous 76 years!  What's even more surprising, is that this has happened as the overall amount of snowfall in Victoria has decreased: from 1914 to 1989 average annual snowfall at Victoria Gonzales was 29.9 cm, while from 1990-2019 the average annual snowfall in Victoria was just 16.4 cm.  So why has the frequency of White Christmases increased?  It's really just up to random chance - the very infrequent snowfalls that we get in Victoria have just happened to occur at or just before December 25, giving us White Christmases.  2017 was a good example of that fortuitous timing of Christmas snow: it snowed overnight on Christmas Eve, providing a White Christmas, but it was melting by evening and all gone by Boxing Day.

Victoria averages 4.7 days per year with 2 cm or more of snow on the ground.  On any given day between November 1 and March 31, there is a 3.1% chance of having snow on the ground.  This likelihood peaks during the last 10 days of December and the first 10 days of January, as shown in the chart below.  During that 20-day period, which includes Christmas, the chance of having snow on the ground ranges between 6% and 9%.

Average Frequency of Snow on the Ground in Victoria (1955-2019)

How does Victoria compare with other locations Canada?  The chart below compares the of having a White Christmas for several cities across Canada.  To make the comparison, I have used the 1955-2019 period, for which data is readily available for a number of locations.  In Victoria, there were 5 White Christmases during this 65-year period, resulting in a 7.7% chance.  Vancouver had 6 White Christmases during this period, or a 9.2% frequency.  As shown in the chart, other Canadian cities have significantly higher chances of a White Christmas: in Toronto it's 47%, while Calgary and Halifax have a 56-58% chance.  White Christmases are almost assured in most other major Canadian cities, ranging from 75% in Montreal to 98% in Winnipeg.

Chance of a White Christmas for Selected Canadian Cities

Given that Vancouver averages 8.6 days per year with at least 2 cm of snow on the ground versus 4.7 days for Victoria, it's surprising that the chance of a White Christmas isn't much greater in Vancouver.  Again, this seems to come down to random chance.  While Vancouver only had one more White Christmas during the 1955-2019 period compared with Victoria, those White Christmases have been much snowier in Vancouver.  For Victoria's 5 White Christmases, the average snow depth was 7 cm, while for Vancouver's 6 White Christmases, the average snow depth was 20 cm.

So if White Christmases are pretty rare in Victoria, what does the weather typically look like on Christmas Day?  Based on the 30-year "normals", the average high temperature is 6.8 C while the average low is 3.1 C.  The daytime high on Christmas Day in Victoria is between 5 C and 10 C 67% of the time; it's between 0 C and 5 C 23% of the time and between 10 C and 15 C 10% of the time.

On average, Victoria gets 2.6 mm of rain on Christmas Day, although there has only been measurable rain on 51% of Christmases.  The wettest Christmas Day was 1972, with 51 mm of rainfall.  Meanwhile, Victoria averages 2.4 hours of sunshine on Christmas Day, or about 30% of the 8 hours that is possible on December 25.  There has been at least some measurable sunshine on Christmas 63% of the time, so Victoria is more likely to get at least some sunshine on Christmas Day than to get some measurable rain.