Every year on Lake Winnipesaukee,
Ice-Out.com is devoted to progressive aerial photos of the ice receding on Lake Winnipesaukee. It's a co-operative volunteer effort between Emerson Aviation (It's Dave Emerson who officially calls ice-out each year) and the great aerial photographer I have had the pleasure of meeting, Bill Hemmel of http://www.aerialphotonh.com/ . Here you can also see and purchase some of the finest aerial photography in the state.
"Ice-out" does not mean that all of the ice is gone. It is actually the moment when the M/S Mount Washington could cruise to all five of it's ports: Alton Bay, Center Harbor, Weirs Beach, Meredith and Wolfeboro. The earliest recorded ice-out (in 135 years) was March 18, 2016! The latest was the very cold winter on May 12, 1888.
Always check out the progress on Lake Winnipesaukee on Ice-Out.com
As for other lakes in New Hampshire, the NH DES VLAP began tracking Lake ice-in and ice-out dates in 2011 as there was no central repository for this information in New Hampshire. Many New Hampshire lakes have historical ice out records dating back to the early 1900's, Lakes Sunapee and Winnipesaukee to the 1880's, but not as much data exists for ice-in records. Tracking both ice-in and ice-out allows the determination of total ice cover days which is another important part of tracking physical, chemical and biological changes to lakes over time. With the erratic weather conditions experienced in recent years, the information can also help track climatological shifts and trends.
Here is a link for detailed Ice-in and Ice-out dates for other lakes.
Whatever you do don't walk, drive on or take a snowmobile on any frozen lake without knowing how safe it is to do so. That is another story for sure.