Some data I grabbed from the great calendar on
http://www.winnipesaukee.com/tempcal/index.cgi
Last year the water wasn't at the 5th day of 37 until April 11. (ice out was :
april 19)
2010 the 5th day of 37 was Feb 24, with a record ice out of March 24.
2009 the 5th day of 37 was Apr 1st, with an ice out of: April 12th
2008 the 5th day of 37 was Apr 16, with an ice out of: Apr 23
2007 the 5th day of 37 was Apr 1st, with an ice out of: Apr 23
2006 the 5th day of 37 was Mar 29th(38F) with an ice out of April 3.
So we are 6 days earlier than the record, which if linear would predict an ice out of March 18th. But we are 40 days earlier than the next closest ice out in 5 years. And that would (if linear) give us an ice out of April 3 - 40 days = ~Feb 24....
Of course, we know there's no magic answer....From reading other posts I gather that the melting process is strongly dependent on what's on the ice, and how sunny it is, the uncovered ice acting like a solar cover on a pool, etc. Then when the ice is really rotted -- what day will bring a strong blow of wind to really knock it apart.... There's some great footage of an ice out in Alaska in the film, "Alone in the Wilderness" where Dick Proenneke discusses the breakup of the ice in the lake where he built his camp. (The book - Alone in the Wilderness - is very good, too.) Winter is a bit colder there... Ahem... -45F....