Im not bald yet but I can say this must be an absorption and color thing.
Wearing a black shirt vs white shirt in the sun type deal.
Many things can factor I suppose, even air circulation. I remember using my pyrex glass containers to cook my leftover steak on a sunny day on my dash. On a 90 degree day on my black dashboard, I managed to get a steak to a whopping 145degrees in time for 12 o clock break.
The probe being metal could potentially reflect heat. The air could be one temperature and the plant itself could be another temp. Any one have a cheap heat gun laser thingy? Maybe check the actual temp of the plant vs the air? We need somebody who knows how to toss around vocabulary words like radiant heat and convection lol wheres @Somatek lol
To answer your question all my efforts are to keep my tent under 80 Fahrenheit.
