For months now, Seattleite Ben Tesch has been working on cumul.us, a next-generation weather prediction site. The site launched just a few weeks ago, and represents a new approach to weather forecasting based on the wisdom of crowds -- in short, the notion that a bunch of people (both expert and amateur) predicting the weather will make better predictions in aggregate than single sources alone.
Firstly, the site will combine as many possible sources of weather forecasts as possible. No one source is ever right all the time, so the idea is that if you aggregate them together, you don't need to check several sources and you get a safer, more accurate forecast. If you also track all of these sources and check their accuracy over time, you'll be able to actually see which ones are more accurate than the others.
Secondly, you can predict the weather yourself. When you make prediction for a particular time and place, the site will go check all of its data sources and record what really happened, and give you a score based on how right you were. It could turn out that a random person is a better predictor of the weather than a professional meteorologist or organization. That person could even be you. Since the site will be tracking the accuracy of all of this, you'll be able to see who is more right, and follow them.
Thirdly (is that even a word?) the site will give you information on the real reason you check the weather: to find out what you should wear. As people submit what they are wearing, it goes into the aggregation of what everyone is wearing in order to suggest to other people what they should wear.
By combining professional weather forecasts with amateur ones (that are scored for accuracy), cumul.us represents an interesting experiment for our age. Head on over and start predicting! (Note: if it auto-selects Seattle as your city, click on the city name to change to the right one. If you create an account, the site will remember where you're from -- and will let you make predictions.)