I use a higher than average lye concentration to help speed up the drying (not curing) process, but soaps made in the summer still take longer to dry. Airflow helps with the initial drying, but once the soaps are almost dry I think it’s a losing battle if the temperature and relative humidity are high. In my experience, even “dry”, well-cured soap equilibrates with the ambient humidity. I realized this after sending soap to Arizona a couple of years ago. All the bands fell off. I have now sent or taken “dry” soap from Virginia to Arizona on multiple occasions. It shrinks every time!