Back in Oct. when I stuck my Vantage Vue up on the roof, I was concerned that, come the blistering hot summer, my temp readings would be too high for the lack of an aspirating fan.
But hmmm, my readings have been spot on with nearby airports expensive stations, day after blistering day (it's currently reading 101 degrees outside and climbing).
With the trees and other houses around me, I had no choice but to put my Vue up over 25 feet above the ground. Perhaps by doing so, I unwittingly compensated for the lack of the fan
Of course, now I read that with no fan, my low temps at night might read a smidge cooler than ambient because of a "small, black-body radiation effect". Something only a meteorologist could measure (less than a degree).
At any rate, it seems to be working out just fine. Waiting with paranoia for the "low battery" message.