Combining heat and alcohol is never a good idea, and it's particularly important to avoid doing so if you're going to be driving. Alcohol is a diuretic, and that means it actually increases your risk of dehydration. It makes it harder for your body to control its own temperature.
As alcohol interferes with your body's ability to regulate itself in the heat, you put yourself at risk for heat sickness. You become more prone to passing out and could lose focus or muscle control more easily. With dehydration, it takes less alcohol that usual to cause intoxication.
How can you prevent drunk driving-related incidents?
First, don't drink and drive in the first place, but remember that even one drink will impact you differently in the heat. If you want to stay cool in the sun, turn to ice water instead of a beer or other form of alcohol.
Try to drink at least 16 ounces of fluids an hour, and make sure to replace the minerals you lose through sweat by trying sports drinks or those fortified with minerals. Wear a hat and choose lightweight clothing. If you're in the sun, wear sun protection, like SPF 15.
If you're involved in a drunk-driving accident or are stopped for driving under the influence, you have a right to defend yourself. You may not have realized the danger heat posed, and it's important to show the court you've learned from your errors. Your attorney can help you fight the charges against you, so you can clear your name and move on with your life without damaging OWI or DUI charges.
Source: Hazelden Betty Ford, "Heat and alcohol--a dangerous combination," accessed June 02, 2017