The weather station you pointed out had a low of -38.7°F reported on Weather Underground. It's in Rome, OH and it's a Davis Vantage Pro.
http://www.findu.com/cgi-bin/wxpage.cgi?call=DW3607&last=72
The temperature readings seem accurate, although the barometer is not.
http://weather.gladstonefamily.net/site/D3607