I moved to Seattle from Calgary two years ago. Weather basically never changes. All cloudy with occasional drizzle all winter, slowly turning into blue skies for a couple months in the summer. We actually had three thunder storms this year, which is a lot. The one time it hailed everybody in the bar was at the window taking pictures. You don't really need an umbrella, outside of a few days a year, but I would recommend a hat or a jacket with a hood.
As for hockey, I get all the Flames games on game center live. I've heard good things about
The Angry Beaver, but haven't gone myself.