I agree with stapfam. I live maybe 40 miles from his part of the world and it has been a really unpleasantly wet summer. My local trails are mostly in the forest area near home and the undergrowth is mostly dry but roots can be a serious hazard. Take one of those at a 45 degree angle and it's down you go. Not so bad in the dry but the wet gets everywhere. I like it though. I have the trail mostly to myself and apart from some piles of horse sh1t (I enjoy riding over them!) the wet keeps most people away. The only thing that discourages me is having to wash the bike after. The dry dust is fine, but the mud and general trail crud can be difficult to wash off. I tend to dress for a dry ride and take my chance.
Last year in Wales I did the mtb trails at Coed Y Brenin and it tipped rain almost every day. I hit the trailhead at about 7.30 each morning and rode until 11 and I dressed sensibly for the rain as I did not know where I really was, and not knowing the exit points on the trail meant I had to dress for the worse. I found the condensation inside the jacket (it was Goretex) was more annoying than the rain.