Last year today it was -23F here in the morning. The Wind Chill was at -42. The daytime high only made it to -12. The next day it was -30F in the morning and made it to a daytime high of -7. I got these reading off a Vantage Pro 2. Being this cold I wondered if the VP was reading correctly? I also have 2 Mercury Thermometers in the backyard. Both said that the VP was correct.