Racer's Lounge - track temps?

might be a newb question but just wondering what is the coldest most tracks allow you to run at? theres a midnight madness event tonight at our track (gateway, madison, il/st louis, mo) and its supposed to get cold. someone told me lower than 50 and they shut it down?

i know one of the tracks here has test and tune nights from 7-11 pm all the way into november so they run in 50-* weather. im sure each track is different though.