This page contains general information on layering, so please check out the links at the end of the article for more detailed information.
Do a research according to the activity you will be undertaking such as going on a hike, expedition or other, taking into to account the season and weather conditions expected etc.
Clothing is your first line of defence or primary shelter against the elements in a time of an emergency, so always dress right for the occasion and the season to be prepared for the worse should it come. Dress in layers to enable you to more properly regulate your body core temperature.
Have a breathable exterior layer called the outer shell that is waterproof and windproof. This permits sweat to escape, but prevents rain or other wet precipitation from penetrating to your inner layers.
While on the move or otherwise exerting yourself as while building a shelter, you can remove a layer(s) to avoid overheating, and to add a layer(s) to avoid becoming too cold when you are at rest. Avoid sweating in cool or colder temperatures, because you risk the possibility of becoming hypothermic. Do not overexert yourself and dress appropriately to avoid any problems.
Clothing materials vary a lot. Gore-Tex being a popular synthetic material is a good quality, breathable garment, however it does have its drawbacks. It can be expensive, might not be sufficiently tough for certain conditions, and is sensitive to heat such as sparks from a fire. My survival instructor at a school that I had participated in, recounted his sad experience he'd had with his expensive Gore-Tex jacket while tending a fire. However, as with any product, manufacturers are always trying to come up with a better product to sell, so do a research concerning Gore-Tex to see what improvements they have made if you want to purchase Gore-Tex garments.
Polar fleece is an excellent material for the base layer because of its wicking properties, and polyester may used as well in the layering system. Synthetic materials tend to retain body odor, while wool does not. However, if you are going through an emergency, being well dressed is what's important, and having a personal hygiene program will enable you to reduce any odors. Also, in order to avoid any possible medical problems such as rashes or infections, have a routine to wash yourself and your clothing.
Try to keep your clothing as clean as possible as well, and wash them if needed and if possible, so that your clothing will give you peek performance in regulating your temperature. Dirty clothing, meaning muddy, water-logged and sandy etc. will clog the pores in the material reducing its effectiveness. If your clothing smells of body odor, don't worry so much about that because the material will still be effective enough. However wash your clothing if possible every now and then to get the best you can out of them.
Cotton is to be avoided like the plaque in cooler climates. The expression COTTON KILLS is not without merit. The problem with cotton is its ability to retain moisture, which is dangerous in colder temperatures. You need to remain dry, or at least be able to dry off. There are several ways in which the body loses heat, and one of them is by convection. The wet cotton will 'pull' your body heat away from you and combined with the right conditions such as cold temperatures, wind and rain can spell danger for you. Any combination of conditions may be sufficient for you to become hypothermic when cotton is involved. Becoming wet such as if your canoe capsized on a cool sunny autumn day combined with a brisk wind may be enough to cause you serious problems.
The wet garment will pull or wick heat away from your body at a rate of at least 25 times faster than if it were dry, and cause you to become hypothermic. Once wet, it loses its insulative properties and can be very difficult to dry. Cotton is good for warmer climates, where you want to avoid becoming hyperthermic. Convection then becomes a good principle, at least to an extent, in aiding the body at retaining a normal body core temperature of 98.6° Fahrenheit or 37° Celsius.
Have a look at what is available out there for other types of materials, and decide what is best for you and for your family. It doesn't need to be expensive. If you do not have the budget for new clothing, you can have a look at some second hand clothing stores. Even army surplus stores may have something of value.
At the very least, have some decent clothing for those occasions where you know you will be more vulnerable to the weather conditions such as going out on a hike or hunting.
Even if it is a beautiful sunny autumn day where the high announced will be 20° Celsius, do not leave your jacket or extra sweater behind in the trunk of your car because you think you'll be hot in it. Remember that if an emergency happens while you are out there, and you have to spend the night on the mountain, that the temperatures may well go down to around 5° Celsius overnight, and couple that with a brisk north-westerly wind and you'll feel even colder. Hypothermia is a real risk at such a time, especially if it rains and you are wet as well.
If you are able to, have a change of clothing appropriate for the season in your 72 hour kit, car kit, office/work and school kits if you desire to, and that way you'll have some good clothing to protect you and your family in an emergency situation.
The best thing would be for you to wear the right clothing to begin with at all times every day where ever you are. Then, if an emergency happens, you already have your primary shelter protecting you. Clothing in your kits then become your spare clothing. Be certain to include in your kits, mittens or gloves, a hat to protect your head and a scarf or dickey garment to protect your neck as well.
Remember to have good footwear. Your feet need to remain dry to avoid skin problems such as blisters. I know it isn't always possible to keep the feet dry if you are out in the woods, but do your best and have a change of socks (or two) as well.
Layering is a head-to-toe necessity in very cold weather. Depending on many factors such as the season, precipitation that may be encountered, type and level of activity, you'll need to select what is best for you. Do a research for more complete information about the layering process as well as the different types of materials and products that are available.
Here are some links to help you out. Talking to someone who is knowledgeable on the subject will help you a lot as well.
1. Trailspace – Layers of fun: Winter hiking essentials
2. Trailspace – Soft Shells 101
Also have a look at the Survival Tips and Tricks page for more information, but on what to do if you do not have the appropriate clothing you need while being in an emergency situation.
Some people like to wear shorts in the wilderness and perhaps under certain conditions it is alright, however, for me, I feel it is more of a liability and a potential discomfort in the event of an emergency.
If I had a recommendation, it is to forget about the shorts and wear pants. Dress as to be comfortable top to bottom.
At the very least if you are going to wear shorts, be aware of the time of the year and weather conditions, as well as how far you intend to go among other things.
Have a pair of synthetic or wool pants along with you. Some pants have the bottom that come off with a zipper going around the pant leg, converting the pants to shorts and vice-versa. Just avoid cotton, and zippers can fail.