Yes ... but the colder water has already moved to the top as it's density decreased once it started getting colder than 39 F. But this doesn't change your point which is correct.Hank49:True the air is not in contact with the water under the ice...but in very cold conditions (-25 F) the temperature of the ice goes well below 32F also. So wouldn't the very cold ice start freezing the water underneath as it comes into contact with it?