Using compressed air to clean out the concrete hole.

[CC Solutions]

Yup. The sensor doesn't have the mass the concrete does, and besides, it's insulated by the plastic it sits in. Just a drop of freezing liquid on the metal sensor contacts and who knows what that does to the readings? So if all the probes are reading 68* and the one I had to blow dust out of reads 50*, I have to let that one re-acclimate!