Let's start with precipitation. On an annual basis, Calgary gets about 35% less precipitation than Victoria - 419 mm in Calgary versus 641 mm in Victoria. If you split that into rain and snow, Calgary gets barely half as much rain as Victoria (326 mm vs. 621 mm) but Calgary gets about six and a half times as much snow (129 cm vs. 20 cm).
Calgary also greatly differs from Victoria in the seasonal pattern of its precipitation. Victoria gets most of its rain in late fall and winter, while the late spring and summer is very dry. In Calgary, the precipitation pattern is the opposite of this, with a very dry late fall and winter, but a decidedly wet late spring and summer. You can see the difference in the chart below. The driest six months in Victoria occur during the growing season, from April to September, with a total of just 137 mm, or 21% of the annual total during that period. By contrast, April to September are the wettest six months of the year in Calgary, with 344 mm or about 82% of the annual total (and two and half times as much rain as Victoria gets during the growing season). During Victoria's wettest months, in November, December, and January, it gets about ten times as much precipitation as Calgary, but during the dry summer months of June, July, and August, Calgary gets four to five times as much rain as Victoria. While Victoria gets more annual precipitation than Calgary, Victoria, on average, is drier than Calgary during five months; May, June, July, August, and September, One of the big reasons for the much drier summers in Victoria is the lack of thunderstorms: Calgary averages about 27 days annually with thunderstorms - nearly all between May and August - compared with about one day per year in Victoria.
We can also compare the frequency of precipitation. For example, Victoria averages 133 days per year with measurable precipitation versus 112 days in Calgary. The chart below compares the % chance of measurable precipitation on any given day throughout the year. There is much more seasonal variation in Victoria, ranging from 60% chance during November and December to a 10% chance in late July and early August. The likelihood of precipitation has a smaller seasonal range in Calgary, from about 20% in November and December up to about 45% in June. The chance of having a day with measurable rainfall is lower in Victoria from late April until mid-September. From late-July until mid-August, Calgary is more than three times as likely as Victoria to get a rainy day. During November and December, the reverse is true, with Victoria about three times as likely to get a day with precipitation compared with Calgary.
As noted earlier, Calgary gets more than 6 times as much snow as Victoria, with an average 129 cm annually in Calgary versus 20 cm in Victoria. Snow also stays on the ground much longer in Calgary, with an average of 86 days each winter with at least 1 cm of snow on the ground compared with 5 days for Victoria. Although on average, Victoria gets much less snow, it has had more really large snowfalls than Calgary. The biggest one-day snowfall in Calgary in the past 100 years was 48 cm in May 1981. In Victoria, there have been three one-day snowfalls that exceeded 50 cm, in February 1916, February 1923, and December 1996.
Calgary does beat Victoria in terms of sunshine, with an average 2,396 hours of sunshine annually, nearly 9% more sunshine than Victoria's 2,203 hours. Victoria averages 315 days per year with at least some measurable sunshine; Calgary gets 333 such days. Looking at the flip side, Victoria averages 50 days each year with no measurable sunshine while Calgary averages just 32 such days. While Calgary gets more sunshine than Victoria on an annual basis, there are some important seasonal variations, as was the case with precipitation. The chart below shows the % of possible sunshine, by month, throughout the year. Victoria gets a much lower percentage of possible sunshine than Calgary during the winter months. In December, for example, Victoria gets just 26% of possible sunshine hours while Calgary gets 46%. However, from May through September Victoria gets a higher percentage of possible sunshine than Calgary. Victoria's summer sunshine advantage peaks in July, when it's sunny 69% of the time in Victoria compared with about 63% in Calgary.
Now let's compare temperature. Calgary, of course, has much colder winters, and it also has a much greater seasonal variation in temperature compared with Victoria. The chart below shows the average daily maximum temperature in Victoria versus Calgary. Average maximum temperatures in Victoria range from 7 degrees in December to 21 degrees in July - a difference of about 14 degrees. In contrast, maximum temperatures in Calgary range from -4 degrees in January to 25 degrees in July - a range of 29 degrees, or more than twice the range experienced in Victoria. The average daily maximum temperature is warmer in Victoria from the beginning of September until mid-May. The greatest difference is in late January, when the average daily maximum is nearly 12 degrees warmer in Victoria compared with Calgary. In contrast, in July the average daily maximum temperature is 3.5 degrees cooler in Victoria compared with Calgary. (It should be noted that the numbers for Victoria are based on Victoria Gonzales, located right on the Strait of Juan de Fuca. Away from the Strait, at the University of Victoria, the average high temperature in July is 23.8 degrees, nearly 3 degrees warmer than Gonzales and about the same as Calgary).
The record maximum temperature for Victoria is 36.0 degrees versus 36.1 degrees for Calgary. Calgary gets an average of 87 days per year above 20 degrees and 5 days above 30 degrees. In contrast, Victoria gets an average of just 50 days per year above 20 degrees and 1 day per year above 30 degrees. Again, if you measure the temperature away from the Strait of Juan de Fuca (at the University of Victoria), it's more like 95 days above 20 degrees and 3 days above 30 degrees.
The next chart shows average daily overnight low temperatures in Victoria versus Calgary. Compared with Victoria, average overnight lows are cooler in Calgary throughout the year. However, there is a much greater seasonal variation in Calgary, so there is a much greater difference between Victoria and Calgary in the winter. Overnight temperatures range from about 3 degrees cooler than Victoria in the summer down to nearly 20 degrees colder than Victoria in the winter. In Calgary, average overnight lows are below 0 from the mid-October until the end of April, and Calgary averages a whopping 194 days per year with overnight lows below freezing. Victoria averages less than 10 such "frost days" per year.
The coldest temperature ever recorded in Victoria was -15.6 degrees in December 1968. On the other hand, Victoria has experienced 7 winters in the past 118 years when the temperature did not drop below freezing. The coldest temperature recorded during the winter of 1925-26 was +1.1 degrees, making it the highest low temperature for any winter on record. In Calgary, the lowest temperature ever recorded was -45 degrees. The highest low temperature for any winter in Calgary was -22 degrees during the winter of 1986/87. In Victoria, the average coldest temperature each winter is -4.8 degrees, while the average winter low temperature for Calgary is -34 degrees.
So who wins the climate smackdown? I think Victoria clearly wins in terms of temperatures. While summer high temperatures are a little cooler in Victoria (at least near the water), Calgary is much colder in the winter, and overnight temperatures are colder in Calgary throughout the year. On an annual basis, Calgary is drier and sunnier than Victoria (although Calgary gets much more snow). However, during the warmer late-spring and summer months, Victoria actually gets less rain and more sunshine than Calgary. While Victoria is much wetter and cloudier during the winter months compared with Calgary, it is also much warmer. While the definition of best climate is subjective, I think Victoria wins this showdown: it has a sunnier, drier summer than Calgary and, in my opinion, a cloudier and wetter winter is a worthwhile trade-off for Victoria's much milder winter temperatures,
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