I spoke to a woman yesterday who, in a kind effort to solve my problem, suggested removing all but one of the leaves on the tomato plant and stop watering it. According to her, removing most of the leaves allows sunshine to reach the fruit and concentrates the plant's energy into making great tomatoes. But I can't do anything to stop the rain. So they continue to get lots of water.
I was also told by a gardener friend of mine that tomato plants should be removed from the ground and hung upside down with their fruit attached to encourage late season ripening.
Any other ideas?