Bizzarely I haven't experienced any temperatures above 25.5 in the recent past!
But I think these are some readings from the wrong side of 0 celsius:
1 1 1 1 1 1 1 1 1 0 0 0
-0.8
1 1 1 1 1 1 1 0 1 1 0 1
-1.9
1 1 1 1 1 1 1 0 0 1 0 1
-2.7
It kinda looks like an inversion of .1 of a degree less than the absolute of the actual reported temp. ie if you invert all the bits you get 7, 18 and 26 I think. I'll give it some thought.