Why bring them? In case you get wet on a cold night or if the night is colder than you expected.

What should I bring? An extra shirt and some pants should be enough. Socks help a lot, you put a fresh pair on just before going to bed and your feet will never get cold before the rest of your body does because your old socks, although they feel dry, still have some sweat soaked up in them and that will lead to cold feet. DO NOT BRING JEANS! This is one place where the magical cloth (denim) doesn't work. They are heavy, absorb 8 times their weight in water, and take a long time to dry (Like two days in the sun kind of long). And when they're dry, they are stiff and very scratchy.