Peeling, flaking paint
About 4 years ago we painted the old house, latex primer under latex topcoat and that over 35 layers of old paint in areas and bare wood in many other places.
None of the paint ever held up well to the sun, porches and shaded areas did much better.
Now I am using a oil based primer and then latex - hopefully this will work better..
Moisture is a prime problem, here it rains a lot, in July , almost every day.
I think at least 3 days of sunshine are necessary to dry the wood.