However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing, kidney problems (such as change in the amount of urine). This is not a complete list of possible side effects.
They are more active when it is cooler, but they can and do come out of hiding at any time of the day. Here in the desert, Arizona Rattlesnakes can easily overheat and die if they cannot find a cool place to keep themselves cool.
Sonoran Sidewinder Crotalus cerastes. VenomousSidewinders are small rattlesnakes that live in sandy desert areas. Most are 2 feet long or less, and move with a distinctive side-winding motion. These are common in the outskirts of the West Valley in washes or flat, open areas.