The climate in New Mexico and the caves within the Guadalupe Mountains will be different from what many of you are used to in your own countries. Many European caves, especially those in the higher altitudes, are very cold and wet. Much of the caving done there involves wearing insulated clothing or wet suits and Welly Boots to keep the feet dry, or at least moderately warm. Not so here in the Guads. The average cave temperature is around 60 F while variations as low as 56 F (Cottonwood and Carlsbad Cavern) and as high as 68 F (Lechuguilla and Hicks/Wind Cave) are about the extremes. Not bad for cave photography, either! In addition to the comparatively warmer caves, the temperatures outside can vary considerably during a single day and you should plan on being ready for some greater extremes.
New Mexico is generally a pretty hot and dry state. Temperatures can climb to over 100 degrees or more during the summer months and we may be hitting the 90's in late April during the ICP Meeting. Because of the quick evaporation of sweat and moisture, you will not notice that you might be sweating a lot and just evaporating moisture away. If you are hiking a long way, you will wind up sweating even more and thus losing body fluids and electrolytes. As such, be sure to drink plenty of water and stay hydrated. You might find that you crave salty foods more than sweets when you are losing a lot of sweat. This is your body warning you that you are in need of salt and other electrolytes in your body to maintain a healthy balance. Loss of potassium can cause cramping and weaken your energy levels. For some people, Gatorade or similar drinks with potassium and sodium will help maintain a healthy balance.
On the other hand, temperatures can drop dramatically once the sun goes down. 80 degrees Fahrenheit during the day can drop to 30 degrees at night over a very short time. The dry desert air has such low humidity that it does not hold the heat at night very well. More than once have I entered a cave in the Guads in glorious sunshine with warm temperatures and come out at night to 6 inches of snow on the ground with more of it falling all the time!! Not much fun.
Here is what most Guad cavers wear on a caving trip: The base layer is skintight spandex-type clothing such as UnderArmor Compression Tights. The body tight fit helps to keep dirt off your skin, wicks away the moisture from your skin when you sweat (because NM has very low humidity, sweat evaporates very rapidly), makes you surprisingly cooler when it's hot and warmer when it's cold. For colder caves and longer expeditions, tights with a slight lining of insulation beneath the outer layer is a bit warmer to ward off the cold. The next layer can be a pullover polyester fiber long sleeve shirt that is warm when damp. It, too, evaporates moisture fairly quickly and dries out in the process. The final layer on the outside is a windbreaker pullover with a hood (not rain proof as it must breathe to allow the moisture to escape) and a pair of zip-up windbreaker pants. It is easy to pull on or take off these different layers for when you are moving through the cave and they compress down to practically nothing in your pack. If there is a lot of standing around to be done, a pull over skull cap to wear under you hardhat helps to keep warmth inside. A piece of thin, closed cell foam in your pack can provide insulation when you sit down on a rock and are still for a long time. If you expect to get really cold, a down-filled hood from a winter parka provides a lot on insulation and crushes down to virtually no volume and extremely little weight. Your head is the biggest radiator of heat of your entire body, so that down hood can be more effective than a complete layer of extra clothing.
These same layers of clothing will work well when you walk to or exit from the cave as well. When walking on a hot day, the tights wick away the moisture and actually feel far cooler with every swing of your arms and legs than bare skin does. When the temperature drops in the evening, the added layers of clothing you can put on for the hike back to the vehicle are usually more than enough. Having that skull cap and/or the down-insulated hood available will do wonders for keeping you warm while hiking. Of course you can always leave an extra layer of warm pull on clothing just inside the cave entrance in case you feel that cold weather is approaching. You just will not need it in the cave which is a constant warm-ish temperature. Overall, having the windbreaker that breathes the moisture away is one of the best ways to keep the warmth inside of you.
Footware is pretty straight forward. A good pair of ankle-high, lightweight boots that allow for a pair of heavy duty socks without cramping your feet and circulation are best. For some people, wearing an ultra-lightweight pair of ankle high womens stockings under those socks will cut down on chafing and help eliminate blisters due to the wicking action of the nylon and the socks. Since the caves in the Guads are generally very dry, there is almost no chance of getting your feet wet.
Like most cavers seemingly everywhere these days, a pair of lightweight rubberized knit gloves work great for crawling, climbing, ascending or rappelling. They tend to keep your hand a bit cleaner and not dirty up your camera gear.
One final thing to mention about the climate is something which is nearly always taking place in the High Guads in particular and that is what we call The Guadalupe Wind. The warm air from the southwest blows across the flat plains and gains some speed until it hits the western escarpment of the Guadalupe Mountain Range. The wind is compressed and speeds up as it climbs the nearly mile high face of the western side of the Guads. When it reaches the plateau of the High Guads, it has increased its speed to upwards of fifty miles an hour and more at times. If you are wet and sweaty when you come out of the cave, you will likely be bone dry before you can even pack up your gear to head back to the vehicles. If nothing else, you will remember the feel of that Guadalupe Wind blowing like nothing else ever does.
For more information about gear for caving in the Guads, go to the Caving Gear Section in the CAVING column on the Navigator menu on the ICPM website.