I haven't had the opportunity to look up the humidity in BC, but certainly it is far greater than what you would see in death valley. Death valley is a very dry area. The Pacific Northwest is wet and the humidity just adds to the misery of the heat. In my area we saw almost 110° at about 35% humidity. I have experienced 120° in 5% humidity and I have to say the 110 felt hotter! Definitely more miserable!