The Minimum Temperatures quoted are guidelines only, drawn from a number of sources. They are the minimum (not average) temperatures which you might encounter in normal weather conditions, so it will often be warmer than this. But it is also possible that it may be even colder if you experience severe weather. It is impossible to cover for every situation, so you need to decide for yourself what degree of caution you build into your gear choices.
The temperatures quoted have not been modified to represent windchill. With sleeping bags windspeed makes no effective difference, assuming you are in shelter. For clothing we have made allowance for windchill in the options presented for each destination and of course all PHD expedition clothing is 100% windproof. However it is worth reading the information on windchill, particularly for destinations where we have indicated that wind can be unusually dangerous.
The TOT (Typical Operating Temperature) and our reasons for using it to rate insulated clothing are explained more fully in Technical Briefings. The short definition is: The TOT figure means that the item is suitable for people heading into situations where these are the minimum temperatures likely to be encountered, for use from short static periods up to medium/low activity.
The single TOT rating we give to sleeping bags is also explained in the same Technical Briefings section.
The aim of this website is to present you quickly and easily with the PHD gear choices most appropriate to your destination and to point out certain things to take into account when making your selection. It is here to help you, but the actual choices remain your own.
Before you go: The more serious the expedition the greater is the value of experience in your preparations. WAYG does not replace experience. So if you have no personal knowledge of your destination, gather all the experienced advice you can to help you make your choices. If you are going with a guided party, the information they give you will be invaluable.
On your expedition: Whatever gear you choose, it is impossible to cover every situation which may arise on an expedition. When extreme weather or accident cut across the most careful plans, good decision-making along with skill and determination become the essentials which will see you through.