Vancouver gets 1900 hours of sunlight a year. That's not a lot. Compare to Seattle (which is considered gloomy) at 2170 hours and SF at 3000 hours.
Are you talking about sunlight or sunshine? I think these are different. The city where I live gets apparently between 1500 and 1800 hours of sunshine, is a bit South of Vancouver (but in Europe) and not particularly known for not being sunny. So the amount of sunshine could actually increase for immigrants, not coming from California.
March or April. We've had an exceptionally harsh winter this year (snow on the ground in Vancouver for weeks on end -- happens about once a decade) but usually around now people are admiring the cherry blossoms on their way to the beach.
Whistler/Blackcomb has a perfectly skiable alpine through to the end of April, and you can ski past that if you want (but I wouldn't personally recommend it).
These are exactly the temperatures tons of people in this thread are saying is cold when referring to San Francisco. They actually correspond with March in SF.
I visited SF for the first time in December and at first I didn't realize why people were complaining about the cold when it was rather nice weather outside (I'm from 60 degrees north) and the weather was in the 60-70 Farenheit range (20 celsius) which I consider to be nice and temperate climate.
But after a week it hit me. It's cold as hell indoors! I have warmer in my house now than I had in my hotel room or office and it's snow and ice outside.
Everybody's perspective is different...
Vancouver does get a lot of concentrated rain, but summers are sunnier than most cities in North America. 90% of that 1900 hours is between June and September.
Sure, further from the equator makes your days shorter in the winter, but they're longer during the summer. It's awash.
If the gloominess happened during long days, you'd really see a drop in mean sunshine hours.