Oh no! You'll miss St. Patrick's Day in NYC which is also DPhiE Founders' Day, but I digress.
Late winter/early spring in NYC. The weather can be anything from freezing and snowy, to wet and rainy, to warm and beautiful.
I recommend taking a tour. The Circle Line is fun. You can go to the Statue of Liberty and Ellis Island. The Empire State Building gives you a great view of NYC and the surrounding area. There are dozens of museums and plays that you could see.
Check out the tourism website for some other ideas.
http://www.nycvisit.com/content/index.cfm?pagePkey=11
http://www.nycvisit.com/home/