When it get's much over 60 F(15C) you need to take care about rattlesnakes when you are wandering around the talus(rock piles) or the cliffs. They are rare, but there is always the chance. If you see one but it dosen't have rattles, then it is a harmless bullsnake and please do not kill it, they eat rattlesnakes.
Black widow spiders are also fairly common to the area.
As awesome as your user name is (I really hope it's your real name), you are sadly mistaken about the dangers of rattlesnakes that don't have rattles. Full grown rattlesnakes often times lose their rattles due to various reasons. Also baby rattlers have yet to develop their rattles and are actually much more dangerous than the full grown rattlesnakes. They have less control on stopping the flow of venom than full grown ones, so can actually be more fatal. Telling people that all rattlesnakes without rattles are harmless bull snakes is irresponsible on your part. You may want to take the time to edit or remove your tip so your ill advice doesn't continue to get misconstrued and lead to a potentially hazardous situation for someone. Also, the idea that bull snakes occasionally eat rattlesnakes is sometimes touted as a reason for humans not to harm bull snakes when encountering them in the wild, although a better reason is the bullsnake's role in controlling warm-blooded vermin such as rodents. Perhaps you should better explain the ecological reasoning behind not harming animals a bit better as well, since all animals that can harm you don't necessarily need to die, but rather just avoided.