I used PSCs as my street/track tires back in CA. I drove them in the rain on several occasions. They hydroplane and you have be careful, but that's no reason not to put them on. I would be very reluctant to run them on the track in the rain, however.
They don't like cold (less than 50 degrees) temperatures. You have to get a few laps into them before asking for 100% on cold days. They can break away quickly on cold days. Not the most forgiving tire, but well worth the compromises.