If you prefer working out outdoors, and with that, you have a stand there, a waterproof punching bag would be a convenient thing. It is a pain in the butt taking it in and out all the time. Who wants to spend time with that.
The problem is that most of the bags cannot stand the moisture and the sun in the long run. The waterproof depends on the material of the shell and the quality of stitching. If the shell sucks the water or the stitching is not tight enough, your bag is going to be a big damp thing that rots inside.
About the materials a little bit.
If you have a leather heavy bag never ever let it outdoor. It sucks the water, and the sun dries it ruining the canvas seriously. You do not want to throw hundreds of dollars away, do you? And, the same is true for shells made from some sort of textile.
Maybe the heavy-duty vinyl is the best options since that material stands the water pretty well, but not sun because of the UV rays. Plus, typically you can fill these bags at the top, closed by a zipper, and it may let the water come through.
So, if you check the materials, you will hardly find one which is sun and waterproof.
What can you do?
You should use some sort of punching bag cover to protect your bag from both.
Maybe you can get a sack or something made from quality plastic material. But, again it is perhaps a bit complicated to put it on and off from the bag all the time.
I was looking around on the web, and I found only one solution on Etsy. This is a hanging boxing bag cover made from Cordura fabric that stands the water really well. Plus, it is easy to put on the bag, and you can choose from two sizes. It protects the bag from rain, dust, sun, wind, etc. And the customer reviews are really positive, although it costs about 50 bucks. You can check out here.
To sum up, I do not know about a high-quality waterproof punching bag, and this cover seems to be the best solution. There are two products on eBay here and here, but I’m skeptical if they are worth to buy.
Have you got other ideas? Share with us.