Victoria's Cold Snap of 2016-17

December and early January is the coldest time of the year in Victoria, but the past six weeks have been unusually cold this winter.  Since December 5, the average daily high temperature at Victoria Gonzales has been has been just 4.4 degrees (compared with the normal high of 7.3 for this period), while the average daily overnight low has been very chilly 0.2 degrees (compared with the normal overnight low of 3.4).  As a result, the overall mean temperature in Victoria over the past six weeks (December 5 to January 15) has been just 2.3 degrees - a full 3 degrees below the normal.  For Victoria, where temperatures tend not to deviate too much from the mean, that is a very significant deviation over such a long period of time.  In fact, we've just finished the coldest 6-week spell in Victoria in over 30 years.  The last time we had a six week stretch this cold was back in November-December 1985.

The chart below shows the daily mean temperatures at Victoria Gonzales over the past six weeks with the 30-year average temperatures for the same period.  You can see that, except for a few days in mid- and late-December, temperatures have generally been well below average.  However, there have been significant fluctuations, with a cyclical pattern of a few cold days followed by a short rebound to close to normal temperatures.

Daily mean temperatures for Victoria  in 2016-17 vs. 30-year average

During this cold snap, overnight temperatures dipped below freezing 21 times - half of the nights in the past six weeks.  Normally, Victoria Gonzales would see freezing temperatures an average of just 5 times during this period.  While we had a lot of days with frost, the temperatures really didn't get that cold during this cold snap - even by Victoria standards.  The coldest temperature recorded during the period was -3.8 degrees on December 17 (and there were only three other days when the temperature dropped below -3).  Victoria gets down to -3.8 most winters (16 of the past 30 winters, for example).  In fact, Victoria has dropped below -6 in 10 of the past 30 winters.

Daytime highs were also well below normal.  Victoria Gonzales even saw one day - January 3 - when the daytime high failed to reach the freezing mark (it was -0.3 degrees).

While it's been cold in Victoria, other locations around the region have been even colder than Victoria Gonzales' mean of 2.3 degrees.  Out at the Victoria Airport, the mean temperature was just 1.0 degrees during this period, and below-freezing temperatures were recorded on 34 nights.  In Vancouver, the mean temperature was a very cold -0.2 at the Airport, although it was a milder 1.7 degrees downtown at the Vancouver Harbour.  Vancouver Airport saw 34 days with overnight lows below freezing and three days when the daytime highs failed to reach the freezing mark.  In Seattle, the mean temperature was 1.9 degrees.   The table below summarizes the average temperatures during the cold snap.

As mentioned above, this is the coldest six week period we've had in Victoria in the past 30 years.  While there haven't been cold snaps like the one we've just experienced in the recent past, they did used to be more common in Victoria.  The table below the coldest six week periods recorded in Victoria over the past 100 years.  I have listed all the cold snaps that were colder than the one we've just experienced.  You can see that the 2016-17 cold snap was the 17th coldest six week period recorded at Victoria Gonzales over the past century.  While the average temperature of 2.3 degrees has seemed very cold, Victoria's coldest cold snap (in 1949-50) was a bone-chilling -2.1 degrees!  Victoria has experienced two other cold snaps when the mean temperature over a six week period has been below freezing (1915-16 and 1968-69).