gear for hot weather
selecting clothing and equipment for hot, arid and humid conditions
In the early 1990s I tried to climb Cerro Aconcagua, which at almost 7000m is the highest peak in South America. I ignorantly assumed that such a high mountain would require cold-weather clothing from beginning to end. However, I soon discovered that far from being a frozen landscape, the walk-in involved hiking through a searingly hot, windblown desert. Enduring temperatures in excess of 30ºC, I ended up sewing a dishwashing cloth to the back of my wool hat in order to keep the sun from scorching my neck. Ever since that salutary experience, I have always researched the destination I am heading for to see what the weather is likely to be. More often than not, I’ve discovered that at least some protection from the sun is usually required.

This booklet outlines some of the options for hot weather clothing and equipment in arid, humid, and high altitude climates. For specific information on individual garments, just talk to a member of Cotswold staff. They have information about, and experience of using, the latest designs.

Paul Deegan

Paul is the author of the award-winning ‘The Mountain Traveller’s Handbook’, published by the British Mountaineering Council and available from Cotswold.
fabrics & protection factors
In extremely hot and dry conditions, more than a handful of experienced explorers prefer the comfort of an all-cotton shirt. In hot and humid weather, things can get a bit more complicated. Pure cotton shirts have a tendency to rot and chafe in damp conditions, whilst at the other end of the spectrum a 100% synthetic, close-fitting lightweight fabric that wicks sweat rapidly from the skin can make the wearer feel very uncomfortable. Invariably, people who spend any length of time in a jungle environment often find that a blend of cotton and polyester turns out to be the best compromise between comfort and durability.

For general travel in warm conditions, a couple of loose-fitting, 100% synthetic shirts (that feel like cotton) can be ideal as they dry so quickly after being washed. The best shirts feature a high number of venting options, a high collar to help keep the sun off the back of the neck, long sleeves to prevent arms from being burnt by the sun, and a long body which enables the shirt to be tucked in.

The materials used in clothing which has been designed for hot weather must be able to perform several tasks. For many people, a fast-drying fabric is important: a garment that can be washed, left to dry overnight and worn again the next day is ideal. The fabric also needs to allow air to circulate freely across the skin, which can help to keep you cool. And the material needs to resist the sun’s rays in order to help delay the onset of sunburn.

In recent years, some clothing has begun to receive protection factor ratings, similar but not identical to the Sun Protection Factor (SPF) rating awarded to suncreams. To date, no internationally-recognised measurement standard has been agreed upon. However, two nations’ protection factor ratings have come to the fore: the British ‘Clothing Protection Factor’ (CPF) and the Australian ‘Ultraviolet Protection Factor’ (UPF). Both tests use a spectrophotometer to measure a fabric’s ability to block UV rays.

The two charts are illustrated below, but it is important to remember that UPF, CPF, and indeed Sun Protection Factor (SPF) ratings are not directly comparable.

It is worth bearing in mind that not all manufacturers subject their fabrics to CPF/UPF testing, so just because a garment is sold without a rating doesn’t mean that it offers no protection. However, because of the vast differences in materials, it is impossible to judge how well a fabric resists the sun simply by looking at it.
The same fabric guidelines for shirts also apply to legwear, although it is worth bearing in mind that trousers are often subjected to more abuse than a shirt. If you are heading into rough terrain, such as a dense jungle, then a fabric that has a ripstop finish might be worth looking out for. (Ripstop looks like small rectangular squares on the face of the fabric. This reinforced grid pattern helps to prevent small tears in the fabric from continuing across the surface of the material.) Other trousers are reinforced with additional panels of fabric on high-wear areas such as the knees and seat.

Try to ensure that your trousers are long enough to be secured over the top of your boots with elastic bands or durable ‘trouser twists’ in order to deter creepy-crawlies.

More than a few trousers sport zips across the thigh. Such zips allow the garment to be converted into a pair of shorts, although it is worth remembering that in some countries, baring large areas of flesh by wearing shorts and sleeveless shirts can be offensive to local people.

Hot environments often demand specialist footwear. For deserts, a boot with a thin canvas upper, a sewn-in tongue and a shock-absorbing sole is ideal for handling both classic sandy and the more usual gravel deserts.

If you are heading for the jungle then it is important to accept that wet feet are inevitable. With this in mind, it is better to choose footwear that sports leech-proof vents, which allow water to easily escape from the inside of the boot. The very best jungle boots are made for the U.S. Army. These can be purchased from reputable army surplus stores. (With the exception of boots, military attire is far from ideal when travelling as it can send out the wrong message to authorities and militia). A boot that sports an integral waterproofbreathable membrane prevents water that gets in from escaping and so is best avoided.

Adventure travellers who are passing through hot and dry or humid environments but are not engaged in expedition-style activities will often find that a lightweight fabric boot or shoe will suffice. Synthetic or wool socks are preferable to cotton blends, which serve only to keep feet damp and prone to blistering.

One of the most important items of clothing for any sunny destination is a wide-brimmed sun hat. And it must be wide-brimmed: a brim that is not capable of throwing the face and neck into shadow is too narrow by far.

Venting holes in the sides of the hat allow air to circulate freely around the crown. Some hats roll up in order to reduce bulk. This feature can be helpful when trekking under a rainforest canopy, allowing the hat to be popped into a pocket and brought out when you step into a sun-kissed clearing. A hat can also protect the face from foliage, which can sometimes be sharp enough to scratch and even puncture the skin. In mosquito country, a head net can be worn over a floppy hat to keep biting insects off the face.

Another popular item of clothing, particularly in desert conditions, is the shemagh. This large piece of cotton cloth can be used to protect the neck, or wrapped around the face during a sandstorm. In hot and humid climates, a thinner cotton neckerchief is sometimes preferred in order to mop sweat from the forehead. The rest of the time it can be worn around the neck to prevent insects from crawling down inside the top of the shirt.

A useful piece of equipment in the jungle is a poncho. This waterproof cape is more useful than a waterproof jacket and trousers because it allows air to freely circulate around the body. (It is worth bearing in mind that in humid environments, even the very best waterproof and breathable fabrics are unable to work properly as sweat vapour is likely to condense even before it reaches the material. Although this can make it feel as though the jacket is leaking, in reality it is probably sweat beading onto your clothes.) When crossing open country in monsoon conditions, an umbrella is perhaps one of the best investments you can make.

So-called ‘crotch rot’ can be minimised by wearing close-fitting, unpadded Lycra shorts, which can easily be washed and dried on a daily basis. If you are thrashing through a jungle with a large cutting knife (known as a parang), then a pair of gardening-style gloves will protect your hands.

Finally, experienced jungle explorers make sure that they always have a dry set of clothing to rest and relax in under their shelter at the end of each day, even if this means climbing back into wet clothing the following morning. Spare clothing can be kept dry by stowing it inside a waterproof canoe bag. Smaller, transparent, canoe bags can also be used to keep maps, electronic equipment and other essential items dry in the monsoon, or when crossing rivers.

dealing with glacial heat
As I touched on in my introduction, it is not just in classic hot weather destinations that one can be struck down by the effects of heat. Even on high mountains, hot weather can take its toll. Nowhere is this more apparent than on glaciers. Trekking across a sun-soaked glacier can feel like an inferno, as the rays are reflected off the white surface and back onto the climber. This explains why mountaineers often suffer from burnt nostrils.

In addition to applying a high factor suncream on every inch of exposed skin, it is important to wear a wide-brimmed hat, or a peak cap with a legionnaire-style rear fabric flap. It is also worth ensuring that your clothing has a high CPF or UPF rating. Mountaineers can do much to avoid the worst of glacial heat by simply starting out on their climb in the early hours, which can lessen the chance of being stuck on the glacier during the heat of the day.

According to one cancer research centre, ultraviolet light at 3000 metres is 50% more intense than at sea level, which makes the use of appropriate clothing and suncreams even more critical than at lower elevations.

As in all hot environments, rehydration is vital. Drink plenty of fluids mixed with additional salts and carbohydrates as appropriate.

repelling insects
Suncreams play an important role in reducing the risk of sunburn. Even a well-equipped trekker wearing a long-sleeved shirt, trousers, sunhat and neckerchief will still have some bare skin – notably the hands – exposed to the sun. The ears, lips and nose are also particularly prone to sunburn, and it is these areas that often develop skin cancers.

Reputable suncreams are awarded a Sun Protection Factor (SPF). The SPF is calculated by comparing the difference in the amount of ultra-violet radiation required to produce minimal reddening of skin protected by a suncream to the amount of UV radiation needed to redden unprotected skin. Using a suncream with an SPF rating of 10 would allow you to stay in the sun for up to ten times longer before burning than had you no cream on. It is important to recognise that smearing additional cream on after the protection time has elapsed makes no difference at all. Whenever possible, do try to stay out of direct sunlight between late morning and mid-afternoon when the sun is at its most potent.

A final sting in the tail: SPFs only gauge the level of protection from UV-B rays. UV-A is responsible for ageing and also contributes to the risk of skin cancer. Protection from UV-A rays is often highlighted using a star system. It’s always preferable to choose a suncream that offers a high level of protection (25+ and maximum stars) from both types of UV.

Many insects are particularly active between dusk and dawn. They include the female Anopheline mosquito which transmits malaria and some other nasty infections. If you are active at this time, a long-sleeved shirt with collar, trousers, socks, shoes and a headnet are all de rigeur. Applying liberal amounts of an appropriate insect repellent – or wearing clothing that is impregnated with a wash-resistant repellent – is also important. (Before applying a repellent to non-impregnated fabrics, check the bottle to see if it damages any materials you may be wearing.)

Other insects, such as the Aedes mosquito which transmits Dengue and yellow fevers, bite during the day. Investigating the destination you are intending to visit before departure will enable you to know not only what to wear but also when to wear it. If you think you will be entering a region noted for its biting insects then take time to find out from your travel clinic or GP which prophylactic medicine (such as for malaria) or innoculations (such as yellow fever) are required. People who suffer anaphylactic shock when stung by an insect such as a bee may require adrenaline; again, talk to your GP before departure.

All outdoor activities are potentially hazardous. The information provided on this site offers guidelines only, and is no substitute for personal instruction from a qualified person. Whilst every effort has been made to ensure the accuracy of the information, no responsibility can be accepted by the author or Cotswold Outdoor Ltd. for any errors or omissions. By choosing to follow any of the advice contained in this leaflet, the reader accepts personal responsibility for a) learning any techniques required, b) any risks involved, and c) any damages or injuries of any kind - including death - howsoever caused. Cover shot: Checking the way ahead on the Trekker's Haute Route, between Chamonix and Zermatt.
© Paul Deegan & Flirt Design under license to Cotswold Outdoor Ltd.