What you need to know about climbing as hotter months bear down.

By Abi Cotler


As winter wanes and we head toward warmer temps, climbing in the heat comes with a whole host of its own challenges. Other outdoor enthusiasts do have to consider many of the same issues; so much of this applies across the board, although I’m sure few hikers or mountain-bikers have ever asked themselves if their feet might burn through their shoes if they head out at the wrong time of day.

According to NASA’s site on Global Climate Change, “Seventeen of the 18 warmest years in the 136-year record all have occurred since 2001.” 2016 ranked the hottest of those with temps in July reaching a record-setting 129℉ in Iraq and Kuwait (the hottest land temperature in the Eastern Hemisphere and, because many meteorologists doubt the Guinness record from 2013, quite possibly the hottest land temp ever!).

So, before things get any hotter here, let’s take a look at what you need to know to stay safe when climbing in the heat.



Former New Mexico adventure guide and avid climber, Manuel Lopez explains, “In New Mexico, we are lucky to have such a dry heat so we don’t sweat our faces off (too much) and smear off climbs. When in doubt, go to higher elevations!”

One of the wisest things you can do when climbing in the hottest months is choose where and when you climb wisely. Try to find crags that are mostly shaded or at a high enough elevation to stay cool—most areas have some.

Articles like this one from Mojagear.com on cool summer climbs and this Mountainproject forum about Red Rocks can help you find them. Lopez suggests Lake Tahoe, Tuolomne Meadows, Castle Crags, and the High Sierras as solid California choices in the summer months.

“I always check the weather for temps and humidity before going out to plan what I wear,” he adds. Again, there are great online resources for this made just for climbers. In the US, try Climbingweather.com and the weather forecast pages on Rockclimbing.org.uk for Europe.



Choosing the right clothes in the heat can make all the difference. Try to find light-colored clothing (to reflect rather than absorb the sun). White, tan, and khaki are all good choices.

Lightweight, loose-fitting clothing that breathes well will also help your body regulate temperature—try nylon and polyester. Clothing with vents is also a great idea and while I have heard more than one female tell her male counterpart that his zip-off pants serve as a natural repellent to the opposite sex, compared to the agony of heat cramps, a little alone time in your zip-offs could sound pretty good.

In terms of fabrics, you may have heard that “cotton kills.” While cotton clothing does absorb a lot of moisture and dries very slowly, if you’re ok with the feel of wet cotton next to your skin and know that it won’t cause chafing if it rubs, wet cotton can feel nice in hot and dry temps (never a good idea for wet or cold climates). Be sure, however, to carry a change of clothes if there’s any chance you’ll still be out in your damp cotton when and if temps dip towards evening.

Other key accessories to consider adding to your summer climbing look is a bandana, sun-protective neck gaiter, or other lightweight cloth that can be dunked in water and worn over your head or around your neck to keep the back of your neck cool and covered while the water evaporates. Special polymer-crystal filled neck scarves maintain the moisture for even longer periods of time.

While the neck is arguably one of the most effective pulse points for cooling down the body quickly, other areas like the wrists, insides of your elbows and knees, tops of your feet, and insides of your ankle are also good places to wrap a cold wet cloth.



Australia’s motto to slip on a shirt, slop on the 30+ sunscreen, and slap on a hat has been one of the most successful health campaigns in the country’s history. Created in 1981 to combat their epidemic numbers of skin cancer, they later added seek (shade) and slide (on sunnies aka sunglasses) to encompass all five of their recommended sun protection measures.

If anyone knows sun, it’s the Aussies, so take heed.

We’ve already discussed seeking shade, so let’s take a look at the other four tips:

  • Sun-protective clothing takes the wise idea to cover up with clothes to a whole new level. Clothing that has a UPF rating is guaranteed to provide protection. Common ratings include UPF 15, UPF 30 and UPF 50+. Learn more on REI’s Sun Protection Clothing Basics guide.
  • For sunblock, start with an SPF 30 or higher and be sure to apply 15 minutes before sun exposure. Also, don’t be sparse; slather that stuff everywhere! Reapply after 40 or 80 minutes of sweating and at least every 2 hours.
  • A hat provides essential protection from the sun for your face and neck. A baseball cap provides ok shade, but a sun hat with a brim that goes all the way around is even better.
  • Proper sunglasses are designed to shield your eyes from damaging sun exposure and can stop headaches and migraines due to bright light, too. The American Academy of Ophthalmology recommends you get those that offer 100% UVA/UVB protection, otherwise they aren’t really worth your money.



It’s true. While hotter temps do afford the ability to eliminate lugging bulky layers of clothes, hats and gloves, they also mean that we need to carry a good deal more water to stay safe.

“I always bring more water then I need,” Lopez said.  “One, because I might need it, two, because someone else in the party might need it, and 3, because everyone has a dog that might need it.”

A good general rule of thumb is to drink about a half-liter of water per hour of moderate activity in moderate temperatures. From there, you may need to increase how much you drink as the temperature and activity intensity rise.

For example, strenuous hiking/climbing in high heat may require that you drink 1 liter of water or more per hour—and yes, don’t forget the dog. I’ve seen several climbers go without because they forgot to account for the pooch and then couldn’t stand to see his tongue hang out in desperation one second longer.

Hydration packs like a Camelbaks are also a really good idea. In addition to the way they save space and weight, having a sip tube always at the ready will make you more likely to hydrate frequently than if you have to reach for a water bottle in your pack. Similarly, as we mentioned in our piece on climbing and nutrition, the electrolyte tablets you can add to your water are also a good, light way to fend off dehydration.

The flip side to dehydration is overhydration, or hyponatremia—a fairly rare condition that mainly affects endurance athletes like marathon runners, but is something that climbers should be aware of. Hyponatremia occurs when sodium levels in the blood become so diluted that cell function is impaired. In very extreme cases, hyponatremia may cause coma and even death.

The symptoms of hyponatremia are similar to dehydration: fatigue, headache and nausea, causing some athletes to mistakenly drink more water and exacerbate the issue. The key to preventing it is to monitor how much you drink. Stick to drinking a few gulps of water about every 15–20 minutes and try not to drink more than you sweat.

It also helps to keep your salt levels balanced by occasionally drinking a sports drink with electrolytes (or water with electrolyte tablets added in) instead of plain water and/or eating a salty snack, such as pretzels.



I remember friends who had just returned from a climbing trip in Thailand telling me they knew it was time to get off the rock when their feet started to burn through their shoes. For anyone who has ever experienced that sensation, it’s enough to never want to repeat it.

Hands and feet are probably of the most critical parts of the body on any climbing day. On a hot one, here’s what you can do to take care of them:

  • Wear the right socks. Stay away from cotton and make sure they fit well. Socks that are too big can have wrinkles that rub and socks that are too small can create pressure points and sock slippage—either way the blisters that can result from ill-fitting socks are not fun.
  • See articles like this one for genius ways to keep your hands dry when the sweat really starts to pour. Gold bond, sage tea, and liquid chalk are three faves.
  • Climbing in the hot sun makes your feet swell, and means your climbing shoes feel tighter. Also, the black rubber of the shoes absorbs a good deal of heat so they can become uncomfortable fast. This also affects performance in terms of stiffness and friction (climbing shoes are designed to perform best in midrange temps.) Don’t sit your shoes in the full sun at the base of the crag. Hide them under a backpack or behind a tree; do whatever you can to keep them cool in between routes.
  • Not only do feet swell in hot weather, skin softens. Add slippery sweat and wet socks from the approach and you’ve got a recipe for blisters. So, again, don’t forget to remove your footwear at every break or belay, let your socks dry in the sun, and if possible dunk feet in a cooling stream or poolit helps with blister avoidance as well as possible core cooling. 



In an article on UKClimbing.com, long distance trail runner Iain Ridgway explains that “When you get seriously hot it’s like your brain becomes somewhat disconnected; you can feel a delay in your coordination…You also get confused and feel very dizzy. The moment that happens seriously think if it’s safe to continueit probably isn’t if you are out alone.”

Advice like this translates well to climbing. The dangers of strenuous exercise in hot environments (see sidebar) are just as serious as other important aspects of climbing safety. The body and mind do not function the same in the heat and it’s important to manage your expectations of yourself and not be afraid to call it as soon as you think you may have had enough.

Pushing yourself on a climb on a cool day may lead to fatigue, sore muscles, or maybe a serious whipper. Pushing it on a super hot day can mean far worse.




Dehydration happens when the amount of water leaving the body is greater than the amount being taken in. 

Early symptoms of dehydration:

  • dry mouth/thirst,
  • reduced urine output
  • darkening of the urine.

As dehydration progresses, further symptoms include:

  • lightheadedness
  • muscle cramps
  • palpitations

Treatment for dehydration

Prevention is the important first step in the treatment of dehydration.

Once it shows up, treat dehydration with fluid replacement of clear liquids such as water, broth, or other replacement fluids that may contain electrolytes (Pedialyte, Gatorade, Powerade, etc.) If this fails, intravenous fluid (IV) may be required.

Heat Cramps

Heat cramps are painful muscle contractions that come on all of a sudden during exercise in the heat. This is a warning sign that you’re pushing your limits and should slow down. To avoid heat cramps, make sure you’re hydrated. If you do get them, gentle stretching can alleviate the pain. 

Heat Exhaustion

This is your body’s inability to cope with the stress of heat. It can occur after lengthy exposure to high temperatures and is often accompanied by dehydration. Symptoms include:

  • Heavy sweating
  • Rapid pulse
  • Faintness/dizziness
  • Fatigue
  • Nausea
  • Headache

Treatment for heat exhaustion should happen immediately

  • Get out of the heat: Look for a shady spot to lay down and rest. Remove any excess clothing. If there aren’t any trees to provide shade, use whatever you have to block the sun.
  • Rehydrate: Drink plenty of water and if you have electrolytes or salt tablets, use some of those.
  • Cool off: Splash cool water on your face and head, dip a bandana or hat in water and put it on your head, or if you can, dunk your head or dip a bandana or hat in water and put it on your head.

Heat Stroke

Heat stroke is a serious medical condition that occurs when your body literally overheats. It can happen fast and requires immediate medical attention. If you see a partner displaying symptoms of heat exhaustion combined with a change in mental status, he or she may have heat stroke. Here are some important indicators:

  • Throbbing headache
  • Dizziness
  • Nausea and vomiting
  • Confusion
  • Disorientation
  • Anxiety
  • Body temperature of 104-degrees-Fahrenheit or

Treatment for heat stroke:

  • Cool down: When there is heat stroke it is imperative that you rapidly cool the person down. Use similar techniques to cooling for heat exhaustion such as getting out of the sun, removing extra clothing, and using cool water and fanning to lower their temperature. If you’re near a lake or stream, you can try to lay them down in the water, but be sure to keep their airway clear. Also, be aware that rapid cooling can cause hypothermia.
  • Hydrate: If the hiker is alert enough to hold a water bottle, get them to drink water.
  • Evacuate: Heat stroke can cause internal organ damage, so get the sufferer out as soon as possible and head straight to the hospital for further evaluation.

If you want to be better prepared to respond to medical emergencies in the outdoors, consider taking a course in wilderness medicine