Despite the recent cold weather, the below December 28th MODIS Satellite Image, with 250 meter resolution, shows that portions of Green Lake and Lake Geneva still have quite a bit of open water.
Green Lake is the deepest natural inland lake in Wisconsin with a maximum lake depth at 236 feet.
Also the image shows little remaining ice in the near shore waters from Sheboygan to Kenosha. Scroll down to see the areas of ice that had been in the near shore waters on Christmas Eve.
The below high resolution satellite image from December 24th shows areas of ice had formed from Manitowoc south to Sheboygan and also in the Racine and Kenosha areas.
The warmer temperatures of the past several days and offshore winds most likely caused the patchy off shore ice to melt.
National Weather Service - Milwaukee/Sullivan