Phoenix has an average summer temperature of around 100 F and more than 300 days of sun a year. This is dry desert heat, so you may not notice you're getting dehydrated until well into the process. Protecting yourself against the sun should be your number one priority, especially if you're planning to golf during the hottest time of the day (between 11 a.m. and 4 p.m.). Waterproof sunblock is essential as are sunglasses and a hat. Long-sleeve shirts may seem like an odd choice for summer, but they can help protect you against sunburn if you have sensitive skin. Bring a water bottle and refill it often to prevent dehydration.
The dry heat of Phoenix requires a mix of clothing.
For summer, think lightweight T-shirts and shorts made of cotton or linen. To go out, casual shirts and pants are fine but choose lightweight fabric that absorbs water well.
During spring and fall, temperatures change drastically between day and night (a 40 degree difference is not unusual), so either dress in layers or bring a light jacket if you plan on staying out all day.
Monsoon-like thunderstorms hit the area between July and September, so bring rain gear as well.
Bring athletic shoes if you plan on going where pavement or sidewalks are absent: The natural terrain is rocky and wearing flip flops or sandals can result in injury.
If you're traveling to Phoenix to play golf, make sure your equipment is packed into a waterproof container, especially if traveling during the rainy season. Also, bring along insect repellent and any prescription medications you will need. While you'll find many pharmacies in Phoenix, you could have a hard time obtaining the medicine if you're from out of state and you can't have your doctor call it in. If you're bringing a camera, keep it inside its case; the heat can damage the lenses and affect the film.
When packing accessories and extras, always keep in mind that traveling light is better. You don't want to be carrying around a heavy suitcase in the desert heat.