I now have four track days (1.5 dry) on the Pilot Sport Cups, and one autocross (dry day) on them. I am very impressed with how well they grip on a dry surface, but it seems that they grip extremely poorly on a wet surface. Today, I was on the track again; in the morning, the track started out wet, and I was a bit cautious. As it dried, I picked up speed. When it was mostly dry, the tires were great. Then the sky opened up, and the last 2/3 of the day were quite wet.

Well, I had an instructor sometimes today, and he noticed that, despite driving very good lines, and gentle application of the throttle, my rear end often was on the ragged edge of going out, at surprisingly slow speeds. This confirmed my impression from other wet days on the track with these tires, but I have only 8 track days under my belt, and I wasn't sure whether it was me or the tires.

Are Michelin Pilot Sport Cups known to be relatively poor performers in the rain, compared to, say, RA1s?

Thanks. Living in Seattle, this actually is an important question!