IPhone 5 Power Button Replacement Programme

I'm afraid you've busted your iPhone. There's no easy solution.

That power button is known to be a weak spot, and submitting the phone to excess humidity (or direct moisture) is never a good idea, even if you weren't planning to be in that storm.

From your description it sounds like the switch is slowly corroding. It will not get better, only worse over time. I'd suggest to have the phone serviced as long as it's otherwise still in good condition, or give up and replace it sooner than planned.

You could also try to repair it yourself by opening it up and cleaning that switch, but it might not even be possible, and worse: you risk breaking your phone. Have it serviced instead.

$150 without being covered by Apple Care warranty is a sweet deal. Our company purchases back the broken LCD from repair shops around the USA and this is really going to be stiff competition. There isn't anyone offering iPhone 5 LCD replacement for under $150 in any retail repair shop around the US. Their all between $160-$200. In the past Apple's repair prices haven't seemed like a business model they wanted to focus on. I'm left scratching my head at what this could mean for their future plans to compete with the boom of iPhone repair shops. I suppose it might not be as big of a deal since there are only so many Apple Genius Bar locations nationwide.