Remember your water, Phoenix
NEVER leave the house without a GALLON of water during summer and a bottle of water during winter! I know...Gallon(?)..but trust me...you'll need every single drop of it.
Leaving the house without sunscreen is considered suicide here!
Definately rent a car if you don't plan on bringing your own. Bus lines are horrible!! I waited once one full hour!!! and the temps. here get up to 120F. Now, if one, at least, had proper shading...but nooo...this is impossible here in AZ. The little Bus 'huts' become so hot that you can't sit without burning (and I really mean burning) your assets and hands.
In summer....DON'T TOUCH YOUR CAR (duh) and don't enter without properly ventilating it first. I know this sounds dumb but hey...why are so many people dying of heatstroke then? I guess Phx is full of educated people huh?
You know...I had to learn it the hard way. We have beatifull Cactai Flowers here BUT they're not that innocent as you may think. Back in '98 I tried approaching a Cactus to make a snapshot and guess what? It attacked me!! Yes..I had a butt-load of Needles and my hands weren't any better. THEY ARE POISONOuS AND EXTREMELY PAINFULL!! THey're either small and round with large white needles or larger with many arms including even sharper and larger needles. Have fun...
We went hiking and all put on sunscreen before we left, with sweating and the dry heat melting it off we looked like lobsters! Not only that we ran out of water and felt like the hike home lasted a century!
Most of these warnings are true, unfortunately it does get extremely hot here and lots of water is necessary. The whole state is a desert so please bring lots of water even in Northern Arizona. A few things to clear up though, Cactus are not poisonous, just painful, very painful. When you are hiking don't be the out of towner on the news that is being made fun of, wear closed toed shoes, bring water, wear a hat, and sunscreen. Don't make your own paths, there is some very dangerous wildlife here and many of them are very small and quick, ie. Rattlesnakes, scorpions, Gila monsters. Also pay special attention to your pets, and children, the valley gets way too many reports of drowning because of improper pool care, dehydration because of lack of water, and it is also illegal to leave children or pets in the car unattended.
Be cautious in the summertime when spending long periods of time outside, especially when hiking. Every year a rescue helicopter picks up a dehydrated hiker of the mountian because they didn't take enough water, and under estimated the desert heat. It is not uncommon for temperatures to reach 115F, or higher in the summer months, so please, spare yourself from being a spot on the news, and TAKE WATER!!
This is the DESERT, so if you decide to go exploring (there are lots of good hikes in the area), be sure to bring plenty of water and sunblock.