Just because the weather is nice where you are and where you are going, doesn't mean you can't get delayed. There's some terrible weather in the Ohio valley and VA right now, and through Central NY. It's very possible your flight might be stuck someplace that is being affected by a storm, and it could even cancel. Best bet is to get to the airport, and see if they cna get you on another flight.
I got lucky yesterday, flying from BUF to MCO via PHL. My original flight from BUF to PHL was delayed by three+ hours, which would have made me miss my connection. They automatically moved me to an earlier flight which was delayed so it was leaving about the time my original flight should have. They were moving people to the earlier flight in the order they arrived at the airport, and when we took off there were 30+ people on a standby list at the gate who were probably stuck in BUF for the night.
Anne