We’ve all been there: It’s a mid-summer bluebird day and the scorching sun is unbearable. The temperature forecast showed triple digits and you’re starting to feel tired as you make your way down the trail.
As you stop to gulp down some water, you ask yourself: Can you hike in 100 degree weather? Is going on an adventure even a good idea when it’s that hot outside?
The short answer: Yes, you can hike in 100 degree weather, but it’s not a smart move. Hiking when the temperature is well in the triple digits puts you at a very high risk for a life-threatening condition called heat stroke. In other words, when the temps are that high, it’s best to stay home.
But as is the case with most things in the outdoors, there’s more to hot weather hiking than meets the eye. In this article, we’ll take a closer look at the challenges and dangers of hiking in extremely hot conditions so you can be prepared for your next trip in the great outdoors.
Is It Safe to Hike in 100 Degree Weather?
No, it’s generally not safe to go hiking in 100 degree weather—unless you’re very prepared for the conditions that you’ll face on the trail.
Although you can hike when it’s this hot outside, doing so means that you’re putting yourself at an unnecessary risk for a serious and life-threatening medical condition called heat stroke (source).
Heat stroke happens when the body is no longer able to control its temperature, so your core body temperature starts to rise very quickly. The only way to treat heat stroke (source) is to get someone out of the heat and into a shaded location where they can be cooled and re-hydrated by medical professionals—not good.
That said, people do hike in 100ºF (38ºC) weather all the time. While doing so isn’t recommended, if you want to trek in these conditions, you need to have the right gear and know-how for the job.
When you hike in extremely hot locations, the key is to start hiking very early in the day so that you can avoid the mid-afternoon heat.
You’ll also need to bring and drink substantially more water than you think you need (think 2+ gallons) and you’ll need a way to replenish the electrolytes you lose through your sweat. Additionally, anyone hiking in a hot environment needs to have plenty of protection from the sun in the form of sunscreen, sun hats, sunglasses, and sun shirts.
But even with the right equipment, it can be hard to keep yourself cool when the temperatures are in the triple digits. The wise move is to stay home when extreme temperatures are in the forecast. The mountains will be there another day.
How Hot Is Too Hot For a Hike?
There’s no such thing as “too hot” for a hike as it all depends on your personal comfort in warm climates. That said, it’s generally not a good idea to go hiking if you’re expecting temperatures over about 90ºF (32ºC).
When temperatures are this high, hikers are much more likely to become dehydrated and develop either heat exhaustion or heat stroke. This is especially true if you’re trekking through very dry areas with minimal shade as your body will lose copious amounts of fluid through sweat as you walk.
While there haven’t been many studies that look at the optimal temperature for hiking, there have been studies that show that we humans really don’t enjoy walking around outside when temperatures get close to the triple digits.
In fact, one study from Utah State University (source) found that visitor levels to Utah’s 5 national parks—all of which are located in the state’s desert region—leveled off when the temperature reached 80ºF. As the temperatures hit 90ºF, visitor levels to nearly all of the parks plummeted dramatically.
While this study doesn’t necessarily prove that temperatures above 90ºF are too hot to hike in, it does suggest that doing so isn’t exactly comfortable or fun. So, unless you know that there will be plenty of shade and water on your hike, it’s generally a good idea to stay home in extremely hot conditions.
What Is The Best Time of Day to Go Hiking in the Summer?
The best time of day to go hiking in the summer is in the morning, or around 7 AM to 12 PM. As a general rule, the earlier in the day that you can leave the trailhead for a summertime hike, the better.
There are many reasons why the best time of day to hike in the summer is the morning. Hiking earlier in the day provides you with:
- Cooler Temperatures – Barring an extreme weather anomaly, the coldest part of the day is normally right after sunrise while the hottest part of the day is right after noon. If you’re expecting hot temperatures for your summertime hike, venturing outside in the morning gives you the best possible chance to avoid the sweltering heat.
- Lower Chance of Thunderstorms – Many mountain ranges, such as the Rockies, experience regular thunderstorms on hot summer afternoons. If you start your hike in the morning, you’ll have a better chance of making it to the summit and back before the thunderstorms roll in.
- Decreased Risk of Being Benighted – Some hikers prefer to start their summertime hikes later in the afternoon since summer also brings late sunset times. While doing so does help you avoid hot midday temperatures, it increases your risk of being benighted on the trail.
Whenever possible, try to start your summer hikes as early as you can. You might not be happy with your lack of beauty sleep during your morning hikes, but you’ll probably be glad to avoid the hot temperatures and thunderstorms that often occur on summer afternoons.
Hot Weather Hiking: Yay or Nay?
There are no ifs, ands, or buts about it: Hiking in very hot temperatures is dangerous and not recommended for all but the most experienced hikers.
If you come prepared with the right gear and opt for a morning hike on a shaded trail, you might be okay on a hot summer day. But the smart move is to avoid hiking in extremely hot temperatures whenever possible.
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David is an accomplished mountain endurance athlete who has completed over 25 ultra marathon races (follow on Strava). He is most proud of his finish at The Drift 100 – a high elevation, 100 mile winter foot race that zigzags along the Continental Divide in Wyoming. In the future he hopes to compete in the ITI 350 and ultimately the full 1,000 mile Iditarod Trail Invitational that follows the same path as the historic dog sled race.