With more than 90 million annual visitors, Colorado is a magnet for people seeking majestic mountains, wildlife encounters and a plethora of outdoor activities, from world-class skiing to camping, mountain biking, rock climbing and relaxing in hot springs. Fans of professional sports can also find plenty of opportunities to cheer on their favorite teams.

While the state is beautiful and inviting, you’ll want to be prepared when taking a trip to Colorado. Here are some insider travel tips and things to know before visiting Colorado.

Prepare for the high altitude in Colorado

You’ve probably heard that Denver is the “Mile High City.” Why? Denver happens to sit at 5,280 feet above sea level. The elevation and access to the Rocky Mountains make Colorado a beautiful state. But many visitors also get altitude sickness, which means that their bodies aren’t adjusting well to decreased oxygen. (What to do if you have altitude sickness.)

To prevent altitude sickness, it’s wise to take things gradually. Don’t arrive in Denver and head straight up to the ski slopes or to climb a 14,000-foot peak, known locally as a 14-er. Give your body a chance to adjust to Colorado’s elevation before you exert yourself physically. It’s also wise to skip or reduce alcohol and the use of other drugs. Using these substances can make altitude sickness worse.

Drink water and stay hydrated

Colorado has a dry climate. Plus, the higher elevation will make you thirsty. To avoid altitude sickness, drink plenty of water. You’ll notice that locals bring reusable water bottles nearly everywhere they go. Why not make your first Colorado souvenir a refillable water bottle? Then, do what Coloradans do: plaster it with stickers from cool places you visit, fill it up with delicious Colorado water (from the tap, not from streams) and carry your water bottle with you.

Insider tip: Do not drink directly from streams and lakes in Colorado. Yes, the water will look pristine and inviting. But animals have spread a parasite in Colorado called giardia. If you drink untreated water from Colorado streams and lakes, you can get an illness called giardiasis, which causes very unpleased diarrhea, nausea, fevers, cramps and body aches. If you think you have giardia, seek medical treatment right away. Doctors can test you for the parasite, and there are treatments available.

Brace yourself for Colorado’s climate

In Colorado, we often say, “If you don’t like the weather, wait a minute.” Why? The weather can change without much warning. It’s normal to experience big day-to-night swings in temperature. And with the low humidity in Colorado, hot summer days can morph into cold nights, especially at high altitudes. Be prepared.

Temperatures can vary greatly depending on where you are in the state and on the time of year. The state’s coldest months are usually December, January and February, with the average high temperature in the mid-40s and lows in the high teens to low 20s. But don’t expect spring to arrive really early. March and April can be the snowiest months in Colorado. Meanwhile, June, July and August usually boast the hottest average temperatures, but at high elevations in the Colorado Rockies, snowstorms can hit year-round. Temperatures in the spring and fall can vary greatly. It can be in the 70s one day and snowing the next.

When climbing in elevation, generally, temperatures decrease about five degrees for every 1,000 feet of altitude gain. So, a 65-degree spring day in Denver could be a 45-degree day in Breckenridge. Or, it might be sunny in Denver, while a windy blizzard could be whipping up on top of Loveland Pass.

Dress in layers

One way to prepare for Colorado’s ever-changing weather is to wear multiple layers of clothing. If you’re cold, you can add more layers. If you’re hot, you can remove layers. When you leave your hotel, you might feel comfortable in shorts and a tank top, but after a 45-minute drive to the mountains, you may be reaching for a jacket. The same is true in the winter. Wear long johns beneath your ski pants. And dress in layers beneath your ski jacket. If you happen to ski on what locals call a “bluebird day,” you might get sunshine and warm temperatures. On a day like this, you might be able to leave your heavy coat at the lodge.

While hiking, backpacking and camping, layers can be a lifesaver. If you’re rafting or camping during the day, you might be able to wear flip-flops. In the evening, you’ll likely want toasty socks and a warm hat.

Wear sunscreen

Colorado boasts 300 days of sunshine, and because of its elevation, sunscreen is necessary year-round.

Plan and give yourself extra travel time in Colorado

Make reservations

Colorado is busy at all times of the year. Due to the growing number of visitors to the state, many attractions, campgrounds and activities require reservations. It’s best to plan to ensure you can visit top attractions such as Rocky Mountain National Park, the Great Sand Dunes or Mesa Verde.

Be aware of traffic

You must plan ahead when traveling to your destinations or activities. Traffic along many popular routes leaving Denver can be very heavy, and construction and weather conditions are significant factors in travel time.

Avoid rush hours

Avoid traveling during peak travel hours, such as Friday afternoons and weekends, if possible. For example, a typical 90-minute drive from Colorado’s famous ski areas, like Keystone Resort, to Denver can take several hours on a Sunday afternoon, even when road conditions are dry.

Check road conditions and prepare for potential road closures

When weather isn’t optimal, travel can be even slower or roads and high-altitude mountain passes can shut down altogether. Mudslides and flash floods in burn-scar areas, such as Glenwood Canyon, devastated by a forest fire in 2020, can close roadways or cause long detours. During blizzards, mountain passes such as Vail, Berthoud, Rabbit Ears and Monarch, often close for several hours. Always check road conditions at COtrip.org before heading out.

Prepare your vehicle

Stock your car with extra food and water. Make sure you have a spare tire and tools. In the winter months, these items, along with extra warm clothes or blankets, are essential. Snow tires or chains may also be required on specific roadways or mountain passes in winter. COtrip.org identifies roads with chain laws in effect.

Have a competent driver or take public transportation

Colorado has some of the highest mountains in the continental U.S. The state has 830 mountains between 11,000 and 14,000 feet in elevation, with 52 mountain peaks at over 14,000 feet.

This stunning terrain results in winding roads that climb over, around and even through these mountains – as in the case of the Eisenhower Tunnel on Interstate 70. Mountain passes may have snow or icy conditions even in the spring and fall months when there is no snow at lower valley elevations. For ideas on great drives in Colorado, check out Colorado’s Scenic & Historic Byways.

Prepare for steep road grades and winding mountain passes

Colorado roadways can have steep grades between 5-9%. Make sure you use lower gears when going down mountain passes so you don’t overheat your brakes. You can use second and third gears (instead of “drive”) in most automatic transmission vehicles when going down to avoid using your brakes. In a manual transmission (stick shift) vehicle, a good rule of thumb on mountain passes is to go down the mountain in no higher gear than the one you were in when climbing the mountain.

If you recognize a burning smell coming from your vehicle while heading down a mountain pass, find a safe place to pull over and let your brakes cool down for about 5 minutes. If you’ve reached the bottom of the pass and can safely continue to drive at a slow speed without using your brakes, your brakes should cool down as you drive within a few minutes.

Watch for Colorado wildlife

With abundant wildlife in Colorado, it’s not uncommon to see a herd of elk or deer along your travels. But that also means they’re on the roadways. If a vehicle flashes its headlights a few times as you pass by, it usually means an animal is on the road ahead.

In 2022, in Colorado, more than 4,500 deer died by being struck by a vehicle. And though deer accounted for 62% of all reported vehicle-related wildlife deaths in the state that year, 246 black bears and 47 mountain lions were also killed by vehicles, according to the Colorado Department of Transportation.

Understand Colorado’s laws before you visit

As you drive throughout Colorado, you’ll encounter many cyclists. Almost 20% of adult Coloradans use a bicycle as their mode of transportation, and over 40% ride their bicycle for exercise, competition or fun, according to a study by Bicycle Colorado.

Share the road

State statutes require that motorists provide at least a three-foot clearance when passing a bicyclist on Colorado roadways.

Drive slowly, but not too slowly 

Colorado has a “minimum speed” on many highways and interstates, including roadways over mountain passes. This means that drivers are not allowed to drive at such a slow speed “as to impede or block the normal and reasonable forward movement of traffic.” The exception is when passing a disabled vehicle (more below on that law), road conditions due to weather or for other safety reasons.

Suppose you happen to be “holding up” traffic because you find yourself sightseeing or uncomfortable on the curvy or steep roadways. In that case, you are expected (and legally obligated to) pull off the road at a safe spot, such as a “slow vehicle pullout,” to allow traffic to pass. When the roadway permits, the law also allows you to drive in the right-hand lane available to traffic (look for signs reading “slow traffic stay right,” or on the extreme right side of the roadway until the impeded traffic has passed).

Move over or slow down for roadside vehicles

In 2023, Colorado expanded its “move over” law beyond police and emergency responders. All drivers must move over a lane or slow down by at least 20 miles per hour below the posted speed limit when passing a disabled vehicle (hazards flashing) on the side of the road. Failing to do so is a Class 2 misdemeanor traffic offense and a possible $150 fine (or three points off your license).

Abide by Colorado’s marijuana laws

Coloradans legalized medical marijuana in 2009 and recreational marijuana in 2014. Health experts caution visitors about using marijuana since there are health risks.

Studies show an increased risk of toxic reactions to marijuana edibles. Between 2012 and 2016, one study found marijuana-related ER visits in Colorado increased three-fold.

Before using edibles, read this advice from Dr. Andrew Monte, an emergency medicine and toxicology specialist at the UCHealth University of Colorado Hospital and an associate professor at the University of Colorado School of Medicine who has done extensive studies on marijuana use.

In Colorado, residents are allowed to purchase marijuana from a licensed retailer and possess up to 1 ounce at a time. However, non-residents can only buy and possess one-quarter ounce (7 grams) of marijuana.

Using marijuana in any way, whether that be smoking, vaping or eating, is not allowed in public places, including parks, ski areas and concert venues. And because it is still illegal under federal law, marijuana use and possession is not allowed on federal lands, such as in Rocky Mountain National Park or any national forests in Colorado. Hotel owners can also ban the use and possession of marijuana on their properties, according to the law.

Arm yourself with these insights about Colorado

Remember, Colorado’s beauty comes with its own set of considerations. From traffic nuances and wildlife encounters to legalized marijuana guidelines and climate idiosyncrasies, thoughtful preparation is your key to an enjoyable and safe trip to Colorado.