2004 Chevrolet TrailBlazer - Odd sound

my Chevy trailblazer sounds like a seal when I brake at times. it does not do all the time some times when I first drive it and if it is raining

You need to have your brakes inspected. Many are designed to make a noise when in need of pad replacement.

Some brake pads can make noise when damp. They may still work fine but are annoying. Get them checked, though.