Since the problem first manifested itself when you got some wet weather, try looking at the outside lite housings, and see if you can see water in any of them.
Sometimes a front parking or marker lite will get a rock chip that lets water in, and eventually that fill up enought to short the bulb out, popping the fuse.
Even after they dry out some, corrosion sets in, and in extreme case can corrode things enough for there to be an additional un-intended path for the current to travel in the bulb socket itself. (this may be one of the reasons a mook would intall a 30amp fuse in a ten amp circuit)
One thing that really works well when troubleshooting this particular problem is to just go thru the whole exterior lighting system. It just takes a few minutes to pull all the housings and eyeball all the bulbs. Any dark bulbs are suspect, and any corrosion in a socket should be cleaned so you don't have a bulb go out in the future.
Check each socket for power and ground with a voltmeter.
Now is also an excellent time to do a little preventative maintainance and slather a little di-electric grease on the bases of the bulbs after you clean the sockets. This will help keep the corrosion at bay, allowing the bulbs work better and live a longer life.
If you didn't find anything in the parking/marker lites it's time to pull the tailight bulb holder assemblies inside the trunk and check them for mechanical damage. (I've seen a couple of the the bulb holders get damaged by loose stuff in the trunk trying to escape .)
Good luck, good catch on the wrong fuse being installed in the circuit! /ubbthreads/images/graemlins/applause.gif
Many people overlook the fuse digram that's printed right on the fuse cover, and will put back in what they took out.
That's a bad plan, as they generally find the problem when something starts smoking.
Things will be much happier with the problem corrected, and the proper ten amp fuse installed. /ubbthreads/images/graemlins/smile.gif