Summer in Rocky Mountain National Park is the perfect time to strap on a pack, double knot those laces and head out on one of the many beautiful hiking trials the park has to offer. Ensure a safe outdoors outing by being aware that the weather here can change quickly and the altitude is high. Bring a well-stocked pack and a friend. Local sports shop owners Kirk Bien, Rob Mardock and David Novic share their packing suggestions for outdoor adventures:

MAPS: Know where you're going. Leave early in the morning if you're hiking above tree line; plan to be back by mid-afternoon.

FIRST-AID KIT: You never know when you might need a Band-Aid.

WATER: Exercising at altitudes between 7,500 - 14,000 feet may cause shortness of breath, dizziness and headaches. Counter those effects and the drier climate by drinking plenty of water.

FUEL: Bring snacks, such as protein or granola bars.

HIKING BOOTS: Choose a sturdy pair with ankle support. Waterproof versions help keep feet dry - essential to avoiding blisters.

HEADLAMP: These are hands-free and handy. Especially if night falls before you've made it home. 

WHISTLE: Use it to attract attention and alert wildlife.

RAIN GEAR: Before you leave, check the weather. If it's raining at a lower elevation, it may be sleeting at higher ones. If it's blue skies, take a jacket anyway; storms move in quickly.

SUN PROTECTION: For every 1,000 feet in elevation gain, light exposure increases up to 10 percent, meaning that at 11,000 feet, your skin can burn in just six minutes of exposure. Wear sunscreen, UV-blocking sunglasses and hats with brims year-round.

Now that you have your packing list, check out our list of hikes for all ages. Don't forget your camera to document your discoveries.