Hi @peter.vanamson, thanks for the report! We are not aware of any issues that could produce anomalously cold readings from AIR devices so wanted to dig into this a bit more. I pulled data for yours and some of the surrounding devices and indeed see the cooler readings from the AIRs that morning. AIR 1 is yours, AIR 2 is shbc to your southwest, Tempest 1 is Kelley Ln and Tempest 2 is Pond View Lane both just to your northeast.
The fact that both AIRs agree on those low temps makes a sensor issue seem unlikely, and I am actually wondering if you are observing a true meteorological phenomena. Here’s why: on the morning of the 31st, there was a very steep inversion in place in a very shallow layer right at the surface. The Chatham radiosonde from 8 am Saturday morning (12 UTC Oct31) shows this nicely:
This means that temperatures would be colder lower to the ground and then increase with height. The elevations of each station help tell the story:
AIR 1: 5.18 m
AIR 2: 4.33 m
Tempest 1: 7.62 m
Tempest 2: 11.35 m
CHH Airport: 14 m
So, my hypothesis is that the dense network of stations near you which are at different elevations are sampling the low-level inversion in place that morning, and the two AIRs which happen to be at lower elevations were in the coldest air while it was comparatively balmy for your neighbors’ Tempests up the hill! Does this seem plausible based on your knowledge of the area?