For the past few years I have always used Massabesic lake in Manchester / Auburn as my indicator for ice out on Winni. I go by Massabesic every day on my way to work so it's been easy and kinda fun watching the ice go out there then figuring out when Winni's ice will be out.
For three years in a row now, the day the ice is completely off Massabesic, 14 days later ice out on Winni has been declared. By tomorrow afternoon all ice will be off Massabesic! If my ice out method holds true,
ice out on Winni should occur on March 22.
Remember you heard it here!!
Dan