Been doing some research on states in my area...
NJ: May/June. Best fishing time Apr 1- May 15.
PA: Same as NJ, exception Allegheny mountains / Lake Erie Apr 15- June 1
DE: May. Best fishing time March 15 - May 1.
NY: (Maybe late may?) June. Best fishing time April 15 - June 1. Exceptions Lake Ontario, St Lawrence river and Adirondack mountains, May 1 - June 15.