14 February 2021 central Greece accepted an significant amount of snow, ambient outdoor temperature this started fallen gently at 3 Celsius and at the time of snow fall it did become 0.001 Celsius.
I did use this opportunity to confirm my PRTD sensor calibration, among with my benchtop multimeter calibration this be indoor at 12C indoor.
![Smiley :)](https://www.ittsb.eu/forum/Smileys/default/smiley.gif)
Now I have full confidence in both ( Four wires Probe and DMM).
![Cool 8)](https://www.ittsb.eu/forum/Smileys/default/cool.gif)