I live in Portland Oregon and have a fully built motor that I put a lot of time and money into....I run the Injen CAI system and run it year round with no bypass and have yet to have a problem from it.

Trust me when I say that if I felt the slightest bit of fear of hydrolock I wouldn't run it on my car because the CAI is nowhere near the worth if I fry my engine.

Oh and BTW it rains here more than it doesn't rain so if it were going to happen it would have already