Unless its rained everyday, the compost shouldn't be that wet. But that depends on what you think is wet. Have you got adaquate drainage holes in them bags, perhaps the excess water is not draining away or not draining away fast enough.
One of my plants nearly came a cropper the other day. I noticed the compost in one of my containers was turning green, which I found very odd. On closer inspection, the plant was in a container which was in a more decorative container, which had no drainage hole. Not ideal unless your a bog plant.
Just a thought.....