One of the questions I often get asked is, “How much does it rain on Vancouver Island? Good question. After all, we live here in a temperate rainforest. And the answer, of course, is “It varies!” But it is a considerable amount of rainfall.
I pulled out some precipitation data from the Environment Canada Weather Office site. I selected a few communities from up and down Vancouver Island, and on both the east side and the west side. A chart of the data is below.
Rainfall on the West Side of Vancouver Island
The trends are quite interesting. Holberg, on northern Vancouver Island, gets close to 4 meters, or 12.5 feet, of rain. Wow! That’s a lot of rain! And Tofino, about a third of the way up the island on the west side gets a similar amount, 3.3 meters or 11 ft. But Henderson Lake takes the cake at 6.6 meters or almost 22 ft of rain a year! All these locations are on the west side of the Island.
The “Drier” East Side of Vancouver Island
The east side of Vancouver Island is much drier. At 0.83m, Victoria gets about 4 cm more precipitation a year than Toronto. That’s not much. Less than two inches difference considering that both cities get less than a yard of rain a year. It’s less than ¼ of what Holberg gets. About half-way up the east side of the island is Campbell River. It gets more precipitation, about 1.3 m or 4.4 feet. But still much drier than the west side. Port Alberni lies in the middle of the Island at the end of a long inlet or fjord. The precipitation here is about half of Tofino’s. And Tofino is only 80 km away.
How does this compare to say, a tropical rainforest like Costa Rica? Simply put, the wettest parts of Costa Rica are about as wet as the wettest parts of Vancouver Island receiving over 6 meters in a year, comparable to Henderson Lake. It rained every day for 359 days in one location. But the driest parts of Vancouver Island are actually drier than the driest parts of Costa Rica.
East Vancouver Island Rain Shadow
The lower precipitation levels on the east side of Vancouver Island can be explained by the mountains in the middle of the island. The prevailing winds are from the west. Moisture-laden air is pushed up over the mountains. And in doing this, the air temperature drops and the air cannot carry as much water. It falls on the west side, leaving the air drier when it arrives further east. As the air moves back down the other side of mountain range, it also warms, and it’s ability to hold moister increases. This of course, is called the rain-shadow effect. The further south you get on the east side of the island, the more pronounced this effect becomes. Astonishingly there is a cactus that grows on the southernmost parts of Vancouver Island and on some of the islands in the straight of Georgia, called the Gulf Islands.
The driest months of the year are reliably June, July, August and September. Over the east island, you can count on it raining less at this time of year than in Toronto at this time of year. So unless you want to do some winter storm-watching on the west coast, the time to visit is during these months. Isn’t it handy that it coincides with summer vacations?
About the Contributor:
Long-time Vancouver Island resident, Sandy McRuer, runs Rainbird Excursions, an ecotourism and sightseeing business in the Port Alberni & Qualicum Beach area. He is an ex-forester and avid birder. More of his images can be found on Flickr.
The rainfall amount you quote for Victoria (0.83 m), is actually at the airport, 30 km north of the city. The city itself is in the Olympic Mountain rainshadow, and gets less than 0.6 m of rain annually – which is significantly less than Toronto.
Thanks for clarifying that Steven!
What is the humitiy levels on the island? Looking for less humitiy because of breathing issues.
No idea – definitely damp. You could try the interior of BC or the Gulf Islands (they’re in a rain shadow).
In the summer, humidity levels are generally low – we don’t get the summertime humidity common in eastern North America.
Dave, just to clarify, Victoria gets more of a rainshadow than the Gulf Islands and thus gets lower precipitation.
Steven is incorrect:
http://www.currentresults.com/Weather/Canada/British-Columbia/precipitation-annual-average.php
Victoria proper: over 158 days 926cm
Sidney (Airport): over 155 days 883cm
You are incorrect, Rob.
The only official Environment Canada weather site operating in the City of Victoria is located at Victoria Gonzales. Weather records have been collected at Gonzales for more than 100 years. According to Environment Canada 1971-2000 climate averages, Gonzales receives 608 mm of precipitation annually, vs. 883 mm at the Victoria Airport.
Environment Canada is much more reliable source for climate data than currentresults.com
See:
http://climate.weather.gc.ca/climate_normals/results_e.html?stnID=113&lang=e&province=BC&provSubmit=go&page=276&dCode=0
Also, the average number of days with rainfall at Victoria Gonzales is 129.
Steven is correct.
Check out wiki climate for Victoria not the airport. 600mm precip & 2200hrs sunshines. Hardiness zone of 9a, the same as Northern Florida.
I think that we’ve got this sorted out – rather than let this develop into a long back and forth I’m going to close the comments on this post. I think Sandy’s original intent with this article was just to get folks thinking generally about how rainfall amounts vary depending on where you are on Vancouver Island. Appreciate the input.