to do or not to dew

The house is done and I am putting the last of the paint on the trim of the shop. The last of it was done in the moon light but it look great. I went to help with the last little clean up of thing in the house that took about an hour. It is about 8:30 and I start loading thing up into the truck to go home. I had not pack up my ladder from painting yet. When I grabbed it it felt damp. I look up and the sky was clear. I checked the last part of the paint on the shop and it had started to run off of the building. The dew had come in that night so heavy that it was like rain. Needless to say we will be redoing the last part of the paint when it warms up. Lesson learned some times even when its not cloudy it can be like rain here in Oklahoma.