A thunderstorm woke me at 2:40 AM. All was well when I returned to bed at 4 AM. Later this morning, I noticed the temperature on the web site at 24º. The Davis console then indicated -99.9º.
I found the ISS cover off and the circuitry was wet from the rain.
Removed the circuit board from the enclosure and dried it with paper towels, then compressed air. After an hour in dry air, it seems to be working normally.
It's gonna take days to correct the data archives. I'll leave the data graphs that indicate the failure.
http://www.lexingtonwx.com/