I'm sorry, but I couldn't let these wrong answers sit out there. Dean, the distance from the sun has nothing to do with the seasons--it's due to the angle of the sun's light through the atmosphere. The sun is lower in the sky in the winter and higher in the summer--that is the reason for the change in temperature. And Kip, the earth doesn't warble--it wobbles, but that's a process that takes about 23,000 years and has very little to do with the seasons. And the sun is never directly overhead unless you live on the equator. Nancy, Richard gave you the closest answer to your question, and yes, the angle of the earth's tilt doesn't change (except for the slight precession of the euqinoxes--the 23,000 year wobble I referred to above). Once the tilt is set, it stays at that angle beccause there is no force causing it to change.