What I've learned about locating and placing your temp sensor that ISS siting guidelines don't explain in detail:
LaCrosse, and I don't know how many other manufacturers, recommend placing the ISS (thermo/hygro sensor) on the shaded north side of your house below the eave of the roof. Mount it down away from the eave to avoid attic heat, etc. This location is not the best.
The thermo/hygro sensor being located next to the house gives slower response times to changes in the air temperature. This is possibly due to the house's retention of the ambient air temperature. The structure's temperature is slower to follow changes in the air temperature and the sensor monitors it. Humidity appears effected as well if the sensor is over cement, wood decking, brick, etc. and not grass covered ground.
Siting the thermo/hygro sensor in an open, grassy, area (per NWS/CWOP guidelines) provides measurement of the sunlit surrounding air as well as the ground below. The sun heats the air directly and the grass covered ground below giving slightly higher readings and more accurate readings than a shaded area not exposed to direct sunshine. This can be seen here where I have a temp sensor setup in the open grass w/FARS (D4009) and another setup on the north side of the shaded house (D2642). The airport, 1/2 a mile away is VTCC.
This is probably known by most folks but thought I'd post it just in case it can help someone.
