I live in Seattle, so I pretty much know that it's going to rain from mid-October through June. If, by some unexpected Act Of God, it doesn't rain, it will be cold. (That's the big secret here -- the clouds actually keep the warm air trapped down so it doesn't get cold and snow. If it clears up, the temperature plummets.)
I use FireFox and have ForecastFox set to display current conditions and the forecast for 3 days ahead anytime my browser is up.