I have actually the other approach with weather. I would sign up just because I figure it would be a HOT year in 2011.

If you notice, Disney raised the marathon $5 but the Half $15 so it is the same cost as the Full. Now tell me(as I am an RD), how come it costs the same to run a Half and full with 1/2 the aid stations and takes only 1/2 the time.
I put on a Full and Half next month. Full is $80(including medal, tech shirts and catered steak BBQ lunch). I only charge $45 for all of the same goodies(medal, tech shirts and catered steak BBQ lunch) as the marathon. I don't even have sponsorship money at all.
This explains why I have been hiding for the last 3 weeks(and the next 6 weeks).