Spring: pollen and lovebugs
Oak pollen coats cars, screens, and walls in late winter and spring. Lovebugs show up in late spring and again in late summer, and they stick to walls, windows, and cars. A wash after those swarms keeps their residue from setting.
Summer: rainy season
Afternoon storms and humidity are when algae and mildew grow fastest. The north walls, pool cages, and fences turn green quickly from June through September.
Fall and winter: the best time to catch up
Cooler, drier months are a good time to wash the house, roof, and driveway and have it hold up through the holidays.
HOAs and rentals
Many Kissimmee neighborhoods have HOA standards, and a lot of homes are short-term rentals. Both are reasons to wash on a schedule instead of waiting for a notice or a guest review.