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Rainfall on Vancouver Island
One of the questions I often get asked by guests 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!”
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.
Monthly precipitation at several locations on Vancouver Island
The locations used in the chart
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 location are on the west side of the 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.
All these lower precipitation levels 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. 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.
The driest months of the year are June, July, August and September. Depending on where you are on the island, you can count on it raining less at this time of year than in Toronto. So unless you want to do some winter storm-watching on the west coast. The time to visit is during these months.