Student or Learner
A. We've got a little house ...... the lake. (Above-over)
B. It's three degrees ...... zero today.(Above-over)
I use above for both. But can we use over too?
No. A house "over" the lake would be literally over the water.
When we speak of temperatures we say above or below. (Actually with Fahrenheit we don't normally have to bother distinguishing unless it gets really cold. We can assume it is a positive temperature unless told otherwise. After a cold spell like we just had is the only time people might emphasize that the temperature is above zero. 0 F = -18 C)