Maple Tree Shedding Leaves Early?

I have a large maple tree that is losing many of its leaves early this year. It is still very loaded, but leaves, mostly green leaves are falling off now. We had a very wet winter in Sacramento. Is this previous wet winter causing the leaves to fall early? The tree is still very fully foliaged and looks healthy, but every day there is a ground cover of leaves. This is the first time in 15 years that I have had this problem. The tree usually sheds in October or November. It is an old tree and probably has been in the ground since about 1956.

By WJ Ricks