I am a bit of a fanatic about shooting my bow. I just enjoy it. In fact, I like it so much, I shoot all year. I also know a lot of people like me. I used to manage an archery shop in northern Colorado, and even when the weather was miserable out we would have people show up to shoot indoors at our heated range.
The only problem with shooting indoors, or only when the weather is nice, is that it doesn't really simulate true hunting conditions. For example, I used to use the puffy, yarn-type string silencers when I first started shooting a recurve. They were great. They silenced my bowstring twang and I thought they looked cool. I never had any problems shooting them during nice weather or indoors.
The first time I had an issue was when I shot outdoors in a pouring rainstorm at a deer. Water leaped off my puffs like an explosion from a depth charge trying to blow up a submarine in one of those old Navy movies. Surprise! The lesson I learned was that puffs can gather water and make your bowstring heavier, and your arrows react differently than when the puffs are dry. Oh yeah, and you may get temporarily blinded by the water spray. From that I learned to twang my string by drawing it a few inches and letting it go during a rainstorm. That kept the water from building up too badly.
Another time, while hunting in a snowstorm and watching a nice deer, I really wasn't paying attention to my string silencers. I drew my bow and shot. At first I thought my bow had blown up. Hard ice had formed on my puff, adding a ton of weight to my string. That caused my arrow to fly goofy, which (stay with me here) is the reason I missed.
The loud crack was some of the ice slinging off my puff and slamming into the belly of my limb. Some snow and ice also flew into my eyes, which caused a temporary loss of vision. The only good thing about all that was I thought, for just a few more seconds, that I might have actually hit the deer. Unfortunately, the ice shards melted because of the heat from my warm eyeball, and I saw my arrow sticking in the snow, absent of any hair or blood€¦Surprise!
I'm not saying don't shoot puffs. I'm just saying it would have been nice to not get surprised by my equipment in a hunting situation, especially on things that could have cost me two deer. I know it sounds silly to practice in bad weather, but that's exactly what I do occasionally to check out my gear. I figure it beats learning about issues when I am out hunting.
The advantage to practicing in bad weather, be it rain, snow or just cold temperatures, is that you get to test your archery equipment and your clothing as well. I practice with my hunting clothes on, from my boots to my headnet. If my clothing seems loud when I draw, it gets changed out or put underneath a quieter garment. Same with bulky clothing. If my bowstring is slapping my jacket on the chest or arm, then it is time to do a little custom work. I have used rubber bands, armguards, and even small tight shirts over bulky clothing to keep it closer to my body. I know my words don't paint a pretty picture, but it works.
I try to fine-tune all my gear during bad-weather practice so when I am out hunting I am not surprised at how my gear responds. I have even gone so far as to freeze my recurve and arrows in a large walk-in freezer to test them before going on a polar bear hunt. Interestingly enough the bow shot fine, but the excess wax in my Flemish string made it very stiff. I used lacquer thinner to take out the excess wax, and everything worked fine.
Other things I have learned include the effect of snow and rain on my feather fletching. For example, I was hunting during a nasty day out west, one of those days that starts with rain and then it turns to snow and freezing cold. My feathers had gotten wet from the rain, and when the temperature dropped my feathers froze. When I took a practice shot, my arrow jumped off the shelf, pushed by the rock-hard feathers, and flew terrible. Lesson learned: Use a fletching cover.
I am still a big fan of a fletching cover in rainy or snowy weather. However, the truth is that there are situations where because of the amount of rain or snow, a fletching cover just won't keep the weather out. To combat that, I now often carry one or two arrows fletched with plastic vanes if I am expecting bad weather. I know that a traditional shooter with plastic vanes on an arrow doesn't sound or look right, but it works.
If I am hunting in a downpour, I don't worry about my feathers and I nock my vaned arrow. I advise small vanes only, three or four inches long. Practice to make sure they will fly well for you. You may have to turn your nock some to get them to fly well, but in a downpour, one arrow fletched with vanes may save your hunt.
Of course, there is always the option of just hunting in nice weather and not worrying about bulky clothes, freezing temperatures, rain or equipment issues in bad weather. But then again, if you're a traditional archer, odds are you're half a bubble off level anyway, and you will be out there hunting no matter what.