Possible Clues:

• Having the most precipitation
• Least likely to need irrigation
• Dampest
• Like the Southeast, vis-Г -vis other U.S. regions
• Getting such a lot of water, could give it a rinse
• Like Hawaii's Mount Waialeale, of all places in the U.S.
• Wettest
• Most wet, in a way
• Having the most wet weather