Around Wisconsin they dont make themselves very wellknown at all until Indian Summer kicks in late September to middle October and thats when they start to swarm The article indicates that this is when they start to invade houses for hibernation but the swarms also occur outside as well during this time and you would think theyd be heading indoors when it gets colder not hotter  It looks more to me like they actually start to dramatically increase in population at this time as well not just looking for safe warm places to hide Have there been any studies on what is actually happening