Cathy Burgess reports that the official date for Ice out in 2021 is April 9.
The winner of her contest is Brian McKinlay. I understand his prize is some very old ice cubes from the last ice of 2006, which pair very nicely with 15 year old Single Malt Scotch.
A new graph has been posted as per below. It can be seen at chandossier.com along with a bit of commentary.