Q: Condesation in car problem

I went to get into my new Express Cargo AWD and the whole roof was wet. The headliner was so drenched my dash was wet, and my cup holders were filled to the rim with water. I brought my car up to the dealership for inspection, and they told me that it was condensation build up which was normal in the rainy season. They said to expect it to sweat in the summer, and that I must dry it out daily to prevent it. It’s not an easy chore to just keep it dry. It took almost 4 days to dry with heaters inside the car. After it’s dry and I go about my business then park it the inside is soaking wet again. What could be the cause of this and how can I stop it?