Hi, Something weird happened the other week and I was wondering if anyone here could explain why. I run a pub and our cellar operates at about a steady 11°c all year round (cooler assisted). The other week we were enjoying some pleasant weather for the time of year(16/17°c) then wham! in the space of about 15/20 mins the outside temp dropped to 9°c. The next thing I know someone complains that the beer is warm, I roll my eyes and to pacify them say I'll check the gas, I go to the cellar and the temp is nudging 16°c(in a heatwave[30°c] it only gets to 13°c) So in a general physics kind of way, what went on? PS cooler was working fine!!