Swarm season is right around the corner, perhaps a month away depending on when the cold weather breaks. They can wind up in the oddest places sometimes.
Remember, if you come across a swarm, or one happens across you, don't spray, squish, or otherwise kill them. Call a beekeeper! Swarms are very docile and stings are unlikely unless you physically harass them. No, they're not nesting, they're just resting while their scouts look for a new home. They're just passing through, looking for a new home and a beekeeper can provide one.
These are uncertain times for pollinators and beekeepers; calling a beekeeper when you spot a swarm is a win/win for both! Actually, it's a win for you too, since every other spoonful of food from your plate is made possible by bees. We owe them......