High low thermometers

I have a high, low and actual, thermometer just so that I  can check how well my plant protection is working, last night the low was-2c. but all my plants looked OK, I cover everything with fleece and keep a fan going overnight, it would appear that with moving air the plants don't get frosted

As well as using windmills the vignerons light candles to warm and move the air against the frosts - this article has a stunning photo of them burning last week. https://www.francebleu.fr/infos/meteo/me...1617699499
Our local vineyards (Madiran) have really suffered with the vines frosted