In a sure sign of spring, ‘‘ice-out’’ has been declared on Lake Winnipesaukee. WOKQ radio reports the pilot in charge of flying over New Hampshire’s largest lake made the call at 6:53 a.m. Wednesday. “Ice out” is declared when the M/S Mount Washington boat can safely travel between its ports without encountering ice. Dave Emerson of Emerson Aviation said the temperature of the lake is about 40 degrees. Emerson said the third week of April is usually when ice out is declared. But last year, the earliest ice out was recorded on March 23. The latest ice out was in 1888, on May 12.