Here is temp. and humidity from five radom sampled motes (different ID) 
temp sensor is DS18B20, humidity sensor is Hih6130. Just one reading.
A bit unscientific but to give some idea about variance:

28f90edd03000020  18.25 RH=42.4 T_RH=17.8  
282f74d2020000b7  18.63 RH=42.1 T_RH=19.0
28dae3dc03000076  18.50 RH=39.1 T_RH=18.1 
28bfcddc03000004  18.50 RH=42.4 T_RH=18.7
28bb24ce02000065  18.69 RH=42.8 T_RH=19.1