My recollection is at 40 degrees or just above, now with that being said one has to remember that there is a ton of fish caught thru the ice when the water is at its coldest. I think the 40 degrees and the amount of daylight seems to get them going with the longer day light making the most difference. Next is look for a full moon during that period when the daylight is getting longer and the water temps are getting into the low forties. That usually happens in the month of April and that is usually the peak period.

Yes the old 5 gallon bucket trick works well to help slow you down and you can deploy a couple of extras out if the need arises for little or even no cost.