That's hard to say cause it depends on your roof. Is it metal, shingle, insulated inside? I have a neighbor that has a Davis about 6 ft above his shingled roof and it always reads high, sometimes 4 degrees higher when the Sun goes down due to the heat dissipating from it all the way to midnight. Is that your only mounting option?
In a perfect world the temp sensor should be about 6 ft. from the ground
In a perfect world the temp sensor should be about 6 ft. from the ground