Wear long pants. I know it gets hot in summer, but consider: being a little hot, or getting Lyme disease? Similarly, it's best if you can tuck your pants into your socks to prevent ticks crawling up your pants or if you have those pants with the drawstrings at the bottom that let you pull them closed. Also, if it's that hot, maybe you should just go swimming at the pool instead of hiking.

Additionally, this is pretty much the same advice for avoiding picking up chiggers, which are annoying as fuck if you live anywhere where those are an issue. (And, in some parts of the world, also often carry unpleasant bacteria.)