Dryer isn't drying found lint outside?

My dryer is taking like 3 full cycles to dry a single load of laundry. My lint collector hasn't had too much lint but this last load of white which included towels had a good amount. I removed the hose and there was nothing in it I also removed the back and found a small amount of lint on the bottom of dryer that I removed. So I went outside to check the vent to see if anything was obstructing it and found alot of lint out there in the flaps of the vent and on the ground. I removed all that I could see/reach my hand to get. What could have caused that? Does lint normally go out the vent like that and could all this rain just have caused it to get wet and collect the lint? Or could there be something wrong with my dryer? It is a whirlpool maybe 6 years old working fine until recently when all the rain started.