Re-lighting the pilot light on a water heater

Our water heater is in a little detached shed outside the house and when it pours sometimes it goes out, prob happens once a year and is usually fairly easy to get back on.

Well it happened yesterday in what was prob the hardest rain we've had in the 6 years we've been in the house. This time though I'm having a hard time getting it to come back on. I'm assuming it's because there is still moisture down there as there is a little condensation on the view port.

At first it wouldn't even really spark but after several hours I can get it to light now but when I turn the temp back up it lasts for about 5 seconds before going out.

Long story short, am I fricked or do I just have to wait until some more of the moisture is gone? Any tips on getting it to stay lit?