Showing posts with label Toronto. Show all posts
Showing posts with label Toronto. Show all posts

Sunday, August 14, 2016

Victoria's advantage when the weather is unsettled

We're currently into a perfect stretch of warm, dry and sunny summer weather: take a look at the forecast for Victoria for the next week.



However, it seems like earlier in the summer the weather was a bit more unsettled than usual, especially in June and the first half of July.  While we might complain when the weather's not perfect in the summer, we should remember that compared with other locations in the region, Victoria's weather actually stands out the most when the weather pattern is a bit more unsettled.  When we have a strong ridge of high pressure giving us the sunny weather we're currently experiencing, other parts of the B.C. south coast are usually experiencing similar conditions.  It's when the weather's unsettled that Victoria's climate really shines.  Unsettled weather during the summer might mean a little more cloud and a chance of sprinkles in Victoria, while in other parts of the region they are getting much more cloud and rain.

Let's start by comparing the rainfall in Victoria and Vancouver this summer.  The chart below compares monthly rainfall from May up until today (August 14) at Victoria Gonzales and Vancouver Harbour (downtown).  You can see that Vancouver has clearly had a LOT more rain.

Summer 2016 Monthly Rainfall, Victoria vs. Vancouver

On average, Vancouver gets about three times as much rainfall from May to August than Victoria (240 mm vs. 80 mm).  This year, Vancouver has had five times as much rain as Victoria (224 mm vs 45 mm).

The chart below compares the total May-August 2016 rainfall (up to August 14) at Victoria Gonzales with several other  locations in the region.  Although the Victoria Airport usually gets about 35-40% more rain than Victoria Gonzales during the summer, this year it's been almost as dry.  However, Vancouver Airport (located in a relatively dry part of the Vancouver region) has had more than three times as much rain as Victoria, and as we've seen, Vancouver Harbour has seen five times as much rain.  Nanaimo, Comox, and Campbell River - which normally get about twice as much rain as Victoria during the summer - have received nearly three times as much rain as Victoria this summer. Finally, Seattle Airport - which normally gets about 60% more rain than Victoria during the summer - has received about double Victoria's rainfall this summer.

Total Rainfall, May to August 2016

So during this somewhat unsettled summer, other locations in the region have received even more rain relative to Victoria than they normally do.  We might grumble sometimes when we get a patch of unsettled weather in the summer instead of the endless sunny days that we expect, but we should keep in mind that when it's unsettled here in Victoria, it's probably still a lot better weather than other parts of the region.

While we're talking about the rainfall amounts this summer, I'd just like to comment on another case of it all being relative.  We've heard in the news that Southern Ontario is experiencing a severe drought this summer.  In Toronto, they have received just 45% of their normal rainfall since the beginning of May.  Sounds pretty dry, doesn't it?  The thing is, normal May-August rainfall in Toronto is 300 mm, so 45% of that is 135 mm - or about three times as much rain as Victoria has seen over the same period.  For Victoria, 135 mm of rain during May to August would be an unusually wet summer, and certainly wouldn't be considered a severe drought!  In fact, in 117 years of record-keeping at Victoria Gonzales, there have only been five summers where our rainfall totals have reached 135 mm.  As I said, it's all relative!

Saturday, March 26, 2016

Which has a better climate - Victoria or Toronto?

Our climate smackdown series continues.  Next we'll compare Victoria's climate to Toronto's.  All the numbers below are based on stats for Victoria Gonzales and for Toronto City (not Airport numbers).  

Let's start with precipitation.  On an annual basis, Toronto gets about 30%  more precipitation than Victoria - 831 mm in Toronto versus 641 mm in Victoria.    If you split that into rain and snow, Toronto gets about 20% more rain than Victoria (741 mm vs. 621 mm) and about 6 times as much snow (122 cm vs. 20 cm).  

Besides getting more precipitation, Toronto also differs from Victoria in the seasonal pattern of its precipitation.  While Victoria has a very distinct rainy season (late fall and winter) and dry season (late spring and summer), precipitation in Toronto is more or less the same year round.  You can see the difference in the chart below.  Victoria gets about 50% more precipitation than Toronto in November, December, and January (318 mm vs. 207 mm).  Precipitation levels are about the same in both cities during the transitional months of February and March, and again in October. During the six months from April to September, Victoria gets less than one third as much rain as Toronto (137 mm vs. 451 mm).  The difference is particularly pronounced during June, July, and August when Victoria gets less than one quarter as much rain as Toronto.  One of the big reasons for the much drier summers is the lack of thunderstorms in Victoria: Toronto averages about 28 days annually with thunderstorms compared with about one day in Victoria.






We can also compare the frequency of precipitation.  For example, Victoria averages 133 days per year with measurable precipitation versus 145 days in Toronto. The chart below compares the % chance of measurable precipitation on any given day throughout the year.  Again, you can see 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 much smaller seasonal range in Toronto, from about 50% in the winter down to about 30% in late summer.  The chance of having a day with measurable rainfall is lower in Victoria from early April until early October.  The gap is especially wide from mid-July until mid-August: if you're planning an outdoor event at this time of year it's about three times as likely to get rained out in Toronto compared with Victoria. 





As noted earlier, Toronto gets more than 6 times as much snow as Victoria, with an average 122 cm annually in Toronto versus 20 cm in Victoria.  Snow also stays on the ground much longer in Toronto, with an average of 68 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 Toronto.  The biggest one-day snowfall in Toronto in the past 100 years was 48 cm in December 1943.  In Victoria, there have been three one-day snowfalls that exceeded 50 cm, in February 1916, February 1923, and December 1996.  

Victoria is also sunnier than Toronto, with an average 2,203 hours of sunshine annually versus 2,066 hours for Toronto.  Victoria averages 315 days per year with at least some measurable sunshine, leaving an average 50 days per year with no sun.  Toronto averages 60 days annually with no measurable sunshine.  The chart below shows the % of possible sunshine, by month, throughout the year.  Victoria gets a slightly lower percentage of possible sunshine than Toronto during the winter, from December until March.  However, from April to October Victoria gets a higher percentage of possible sunshine.  The difference is especially noticeable in July and August, when it's sunny nearly 70% of the time in Victoria compared with about 58% in Toronto. 




Now let's compare temperature.  While Victoria has  much greater seasonal variation in precipitation and sunshine compared with Toronto, the opposite is true for temperature.  The chart below shows the average daily maximum temperature in Victoria versus Toronto.   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 Toronto range from -2 degrees in January to 27 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 for half the year, from mid-April to mid-October.  The greatest difference is in mid-January, when the average daily maximum is nearly 10 degrees warmer in Victoria compared with Toronto.  In contrast, in July the average daily maximum temperature is 6 degrees cooler in Victoria compared with Toronto.  (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).  



The next chart shows average daily overnight low temperatures in Victoria versus Toronto.  The pattern is very similar to the daily high temperatures discussed above: there is a much greater seasonal range in Toronto, with average overnight lows ranging from -8 degrees in January to nearly 19 degrees in July (a 27 degree range).  In Victoria, overnight lows range from 3 degrees in December to 12 degrees in August (a 9 degree range, only one third of the range in Toronto).  Average overnight lows in Victoria exceed those in Toronto for an even longer period than the daytime highs do, from early October to early May.  In Toronto, average overnight lows are below 0 from the beginning of December to the end of March, and Toronto averages 101 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 Toronto, the lowest temperature ever recorded was -32.8 degrees.  The highest low temperature for any winter in Toronto was -13.1 degrees during the winter of 2005/06.  In Victoria, the average coldest temperature each winter is -4.8 degrees, while the average winter low temperature for Toronto is -20 degrees.  

The record maximum  temperature for Victoria is 36.0 degrees versus 40.6 degrees for Toronto.  Toronto gets an average of 50 days per year above 25 degrees and 13 days above 30 degrees.  In contrast, Victoria gets an average of just 8 days per year above 25 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 27 days above 25 degrees and 3 days above 30 degrees.  Either way, Victoria's summers are much cooler than Toronto's - and no humidity!

So who wins the climate smackdown?  I think it's pretty clear that Victoria wins in terms of more sunshine, less rain, and much less snow.  It also wins for having much milder winters.  However, the summer temperatures are more subjective.  Being a Victoria native, I love the cool summers here, but I know that some people prefer the heat in the summer.  Give me cool, dry and sunny over hot and muggy any day, although it would be nice to have a few more warmer summer evenings in Victoria!  Overall, I still have to give this one to Victoria.