I think it’s just an association based on the current temps. They just know, as we do, that it’s cold out there. We have had our first 2 nights of freezing temps. and my 2 cats don’t want to stay out long. Just long enough to get a burst of frisky and run back in the house and start bouncing off the walls. lol My female Siamese is terrible, she has so much energy and is a terror every night for several hours when she is cooped up due to the cold and rain.