It is. Everything sounds different, the bike feels different. I think riding in the rain is part of the whole experience of cycling, just like riding on a nice, warm, sunny day.

And within limits, I do think it is possible to stay dry. In Germany, it is not uncommon to see commuters covered head to toe in Gore-Tex or whatever the currently fashionable wp/b fabric is, riding straight through puddles on their bikes equipped with full fenders and Ortliebs.