Ride easy. In the wet it's easy to get your balance thrown off from wheel drag in a deep puddle and/or getting hit with a splash off a passing car. Don't push yourself or the bike as hard as you normally would in the dry. Summer storms come fast in the desert, at least to me it feels darker than it does when it rains here at home because you can still have bright patches of sky that throw off your light sensitivity - so keep hi-vis in mind when you prepare to ride, even if it seems nice out.