I've tried all sorts of stuff but found nothing that works for extended periods so just don't worry about it anymore.
Tuned properly,the arrow will still fly ok wet for close range shooting.
Hair spray worked ok short term.

I used a Quick Spray of Scotch-Guard Waterproofing Spray on Mine for the Cloverdale Rain Forest!!          

Steve, I'll try that. You know how wet it can get here in the late blacktail season here in Oregon!

I have been using unscented hair spray for almost 30 years  If your in a down pour then nothing works  but then in a down pour there is no real blood trail cause it gets washed away  so you should not be there any way .
 NOTHING works for long and a steady rain . But on a mistly drizzly day hair spray works fine . Will collapse on the shot but then you will probably use another arrow  for another shot any way.

"You know how wet it can get here in the late blacktail season here in Oregon!"

NOTHING like SE Alaska!  My suggestion will probably go un-noticed and get mixed in with many of the other inferior methods above.  I came up with the Spar in a can because most of the other methods mentioned above failed.

I use Black Magic tire spray. It does smell, but let them air out and they are fine. Steve if I ever get to come hunt SE Alaska, I will just put bags over my fletch  

yea i got it bro,my legs went numb and my eye startin twitchin like hell when i put it on.hahahahaha...jokin....where do i find this silicone?

I got mine from Tru value hardware store.I can check the brand name when I get home.

"Water Shed"  It is made for fly fishing , if it works for something made to be thrown in the water it realy works!! Can find at any fishing store.

Not totally unnoticed Steve. If it works in SE Alaska it will work anywhere!