Might consider a multi-remote thermometer to monitor temperature in outbuildings.  I have this one to check temp in a couple of buildings.  It comes with a base unit and 3 remote units.  Be careful to not mount the remotes on sun-exposed external walls which can give false readings due to heating from sun.

https://www.amazon.com/dp/B01EI0MS84?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1