If you routinely park around or under trees, you could have some AC problems soon. The issue is the leaves and other things that gather at the base of the windshield, usually under the edge of the hood. This “mulch” for want of a better word, ends up falling into the intake for the AC evaporator case. Of course, the cool & damp environment is perfect for growing your own little science project on bacteria- under your dash. You will soon get the moldy “dirty socks” smell out of the vents and wonder where it came from. Do yourself a favor and stop it before it happens by cleaning your cowl vents every few weeks. You will be amazed at how much stuff gathers there.