Why Drinking Coffee in Hot Weather Might Not Be a Good Idea

Since coffee is a diuretic, drinking iced coffee when it’s blazing hot outside may not be as hydrating as you think. However, pairing it with water helps you maintain hydration.

Is It Safe to Drink Coffee in Hot Weather?

Drinking coffee in hot weather isn’t inherently dangerous. There’s only a risk of dehydration if you’re drinking it in excess without replacing lost fluids.

“Moderate coffee consumption is not a concern for dehydration, even in hot weather, if it is part of a regular drinking liquids routine throughout the day,” Rob van Dam, PhD, professor of exercise, nutrition science and epidemiology at the George Washington University, told Verywell Health. 

Drinking water is crucial for overall health, but is especially key on hot days to replace the fluids lost through sweating and urination.

When Is It a Problem to Drink Coffee on Hot Days?

The main concern about drinking coffee on hot days is that coffee contains caffeine, a mild diuretic that stimulates the kidneys to excrete more water.

Studies have shown that moderate coffee consumption doesn’t cause dehydration in healthy adults because the amount of water in it compensates for the diuretic effects of caffeine.

Van Dam said caffeine’s diuretic effect is more apparent in people who aren’t used to consuming it. Daily coffee drinkers develop a tolerance that lessens its impact on the kidneys.

People who don’t regularly consume caffeine may want to avoid coffee or energy drinks during hot weather for this reason. And while hot coffee may raise your body temperature and increase fluid loss, van Dam said it’s unlikely to do so to the point of dehydration.

How to Stay Hydrated and Drink Coffee When It’s Hot

The key here is moderation. Drinking enough water each day is essential and especially important on hot days.

While people have different caffeine tolerances, it’s recommended that adults consume 400 milligrams or fewer per day. One espresso shot contains about 64 milligrams of caffeine, and one 12-ounce coffee has between 90 and 100 milligrams.

“Listen to your body and cut back if you feel thirsty or experience signs of dehydration,” said Natalie Newell, RD, LDN, a registered dietitian at UNC Rex Nutrition Services of Wakefield.

To stay hydrated while drinking coffee, Newell said to:

• Switch between coffee and water: Drink 12 or 24 ounces of water for every 12 ounces of coffee.
• Get creative: Try infusing water with fruit or herbs for a better taste. 
• Add ice and milk to your coffee: Adding ice to coffee won’t change its properties. However, the colder temperature can be especially refreshing on hot days, and adding dairy or plant-based milk to coffee imbues it with some additional nutrients.
• Try other beverages: Decaf coffee is a great option, as well as iced tea, coconut water, and juices or electrolyte-rich drinks without much sugar.