By Petethomson
West Midlands,
United Kingdom 
I have an electronic thermometer in my greenhouse, which shows inside and outside temperatures and also records max and min for each. It's always a few degrees warmer inside than out when I'm there, as you'd expect ... but the recorded minimum is often lower in than out. Can this be true, and if so why? The sensors inside and out are at about the same height.
17 Nov, 2017
Answers
Might happen if the outside sensor is sometimes in the sun.
17 Nov, 2017
But the minimum temp is normally at night. For starters I'd be tempted to buy or borrow a simple cheapy max and min and put it outside to discover whether the electronic one agrees.
17 Nov, 2017
It sounds improbable to me, Pete! Is the outside sensor near a source of heat, such as a house window, fireplace flue, or water heater outward vent?
17 Nov, 2017