We've all been there. It's really easy to get dehydrated-not to mention sunburned-come summertime. These are issues to be wary of year-round, but they're particularly tricky in warmer weather.

"Staying hydrated in the heat can be more challenging than in cooler temperatures because we lose a significant amount of fluid through our skin in the form of sweat," Jonah Soolman, RD, a nutritionist and certified trainer at Soolman Nutrition and Wellness in Wellesley, Mass. tells Health. Since we need to replace the fluid lost in that sweat, Soolman explains that "our hydration needs tend to be higher than when the temperature is more mild or cold."

A 2004 report from the Food and Nutrition Board suggested that men aim for about 3.7 liters of water a day and women aim for about 2.7 liters a day. But that may change in different environments: Hot or humid weather can necessitate additional fluid intake, as can high altitudes.

Why does hydration matter so much? "[It's] important for several reasons, including body temperature stability, bowel regularity, reduced kidney stone risk, and filtering waste products, just to name a few," Soolman says.

Well, then. Here are tips for hydrating yourself while keeping good-looking.

Invest in a new water bottle

In the same way that a new workout outfit can help motivate you to go to the gym more often, refillable water bottles are gorgeous these days, with all the bells and whistles you could ask for in terms of color, design, and features. Get one, and then bring it everywhere. Our fitness editor's number-one pick: the Nathan Flexshot ($25; amazon.com), which can be easily folded up when it's empty, making it great for travel.

Some of those very same water bottles include features that pester you when you're not drinking enough, whether via a Bluetooth-connected app like in the H20Pal Smart Water Bottle ($99; amazon.com) or a little device that lights up when you haven't moved your bottle recently.