Why The Grand Canyon Can Actually Be More Dangerous During Spring And Fall Than Summer

If you haven't been there, the Grand Canyon is a difficult thing to wrap your mind around. The canyon is located in the Arizona desert, which is dry by definition. Yet most of the South Rim is about 7,000 feet above sea level, which is higher than any mountain east of the Mississippi River. The average width of the canyon is 10 miles, an astonishing distance for a crack in the Earth. The popular Bright Angel Trail will take you to the bottom of the canyon, but you'll have to hike about 10 miles to get there, and even the shorter trail, South Kaibab, is around 7 miles and descends 4,300 feet. Either way, the journey will take you most of a day.

Almost anyone will tell you that Arizona summers are brutal. In Maricopa County — where the capital of Phoenix is located — 645 people died of heat stroke in 2023 alone. Even at these higher elevations, the combination of arid landscape and direct solar exposure can be lethal to hikers.t best, the experience is grueling, as outdoorspeople trudge along dirt paths on the side of a cliff beneath a blazing sun.

At the same time, hiking the Grand Canyon is a popular bucket-list item. The scenery is spectacular, of course, and it's hard to beat such a thrilling back-country adventure. So few people hike the Grand Canyon that they're known as "one-percenters." But if you've studied the climate and concluded that spring or fall are perfectly safe for Grand Canyon trekking, think again: the shoulder seasons are sometimes considered more dangerous since confident hikers take fewer precautions against heat and dehydration.

Most people will tell you that the best months to visit are April or October, which mark a sweet spot for both weather and popularity. But even in these ideal conditions, this remains the most dangerous national park in the country, and any hike around here, including this difficult Grand Canyon hike, is not for amateurs. There are precipitous drops, of course, and the chance that you'd injure yourself in a remote location. But many visitors fail to understand the shifts in temperature — and come under-prepared.

When it comes to Arizona temperatures, elevation is everything. The Grand Canyon is an extreme example: The rim is cooler, and the canyon floor is warmer, so you have to prepare for both climates, plus every altitude in between. For example, the rim receives a good amount of precipitation each winter: It's typical for 142 inches of snow to pile onto the North Rim over the course of the season. But this all transforms into rain or evaporates altogether as moisture attempts to trickle down to the Colorado River. It's not enough to point to one part of the canyon and think, "It'll be highs of 70 degrees, so I'll pack a T-shirt and hoodie." Temperatures can vary by about 5.5 degrees Fahrenheit for every 1,000 feet of elevation. In the case of the Grand Canyon, that's the difference between 70 degrees at the top and 90.65 degrees at the bottom.

Heat isn't everything, though. A parallel threat is dehydration, which makes the water bottle filling stations so vital to hikers. The Grand Canyon is packed with natural springs — about 11,000 across the park — but the landscape is still extremely dry. As the saying goes, "By the time you're thirsty, you're already dehydrated." Too much direct light can also cause sunburn, eye damage, and heat stroke.

Hiking in the Grand Canyon is an extremely customizable experience: You can hike part or all, alone or in groups, going down just a little or crossing from "rim to rim." You can negotiate the steep escarpments of South Kaibab, or you can take this gorgeous and comparatively easy trail for serenity and solitude. The key is to pack the right gear and come with as much knowledge as possible, even in the most hospitable seasons.

The easiest way to ensure your safety is to take a guided hiking tour. The National Park Service arranges day-hikes led by local rangers, who know the terrain and conditions better than anyone and can advise what to bring — and quickly call for help in the event of an emergency. The Grand Canyon Conservancy Field Institute also organizes hikes, which are often coupled with ecological, historical, or photographic instruction. These can be a great learning experience, and institute guides can also advise you on what to bring. Finally, there's an endless directory of commercial and private tours, which may center on hiking but could include jeeps, rafts, and even helicopters as well. 

Whatever group you join, the organizers want you to have a good time — and stay safe on the switchbacks. Seasoned hikers may attempt the Grand Canyon on their own or with a hiking partner or two. This is admirable, but do take some time to review the NPS's excellent online safety guide. And when in doubt, turn back.