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0-65' at 36*F on most lakes. With slight temp changes measured in tenths. Another good read>>>http://www.waterontheweb.org/under/lakeecology/05_stratification.html
Very good information from this link. Water temps are a mysterious thing....if the temp is above freezing, why doesn't the ice melt from below? Points to ponder.... Happy trails.
Water is most dense at about 39f and settles to the bottom of the lake, so the water just under the ice is near 32f. I think oxygen has more to do with fish location than water temp mid to late ice.