During summer months, temperatures in the Arizona desert can reach or exceed 100 degrees every day. Sunset does not bring immediate relief as temperatures can hover around 100 degrees well into nighttime hours. During early summer, the climate is very dry. From late June to early September, temperatures remain hot and humidity increases, inviting dust storms and monsoons. You, your passengers and your vehicle need to be ready for the unique challenges of driving in these extreme conditions.

Before You Travel Plan your travel route in advance.

Notify someone of your route, destination and projected arrival time.

Fill your fuel tank and try to keep it at three-quarters full. Running out of gas — especially in a remote location — is extremely dangerous in extreme heat.

Visit Arizona Traveler Information or dial 511 for updated road and weather conditions. However, never use a cell phone or mobile device while driving.

Preparing Your Vehicle Make sure your vehicle is in good working condition. Having a vehicle breakdown in extreme heat can be very dangerous, especially if you try to repair your vehicle yourself (which causes exertion) or if you must wait for help to arrive. Heat can zap your battery. Make sure your battery is up to par and has enough fluid. Consider having it tested, especially if it's three or more years old. Replace it if necessary.

Check coolant levels and top them off if needed. If coolant needs to be flushed and replaced, do so before your trip begins. Note: Never remove the radiator cap while your engine is hot!

Top off vital engine fluids such as motor oil, transmission fluid, brake fluid and power-steering fluid.

The combination of under inflated tires and hot pavement can lead to a blowout. Check your tire pressure. It should be at the level recommended by the vehicle manufacturer.

Make sure your vehicle's air conditioning system is functioning properly.

"Must-Haves" for Every Vehicle Never drive in extreme heat without a fully-charged cell phone and extra drinking water for all passengers, including pets. Other must-haves include these items: A cooler to keep extra drinking water cold (Consider adding several frozen bottles of water to use for cooling off or to thaw and drink if needed.)

An umbrella for shade

Sunscreen

A wide-brimmed hat, sunglasses and loose-fitting, light-colored cotton clothing to provide protection from sunburn

Necessary prescribed medication(s) and pain relievers

A first-aid kit

A flashlight with extra batteries

A travel tool kit and battery cables

Safety flares

Extra radiator water

Healthy snacks

A road map

Crashes or Other Situations Requiring Emergency Assistance Dial 911.

If possible, move the vehicle out the travel lanes into a safe area.

Try to find shade for everyone; stay out of direct sunlight.

Attend to all medical needs in a safe, shaded place if possible; also, find a safe place to call for roadside assistance.

If your vehicle becomes nonoperational, raising the front hood and activating its flashing "hazard lights" signal to other drivers and emergency responders that it is disabled.

Stalled or Stopped Vehicles Call for assistance right away to reduce your wait time.

Keep your vehicle in a shaded area if possible and run the air conditioner (A/C). If the A/C is not working, roll down all the windows.

DRINK WATER. Make sure everyone, including pets, stays hydrated.

Without air conditioning, the temperature inside a stopped vehicle can rise to a dangerous (even deadly) level rather quickly. If temperatures inside the vehicle become too hot, carefully exit all passengers, including pets. Seek out or create a shaded area as far away from the travel lanes as possible.

Raise the front hood of the vehicle and turn on flashing "hazard lights."