'Twas only yesterday that I took my inaugural ski run, traversing the trails of Bristol, and as I cruised down the mountain I began to reflect on the nature of skiing, particularly waxing. My skis weren't particularly well waxed for the day, so I wasn't going quite to fast, but I did have experience waxing skis beforehand (mostly with nordic skiing - for that it was a weekly affair). When one considers the purpose of wax, it's natural to assume that all it does is make the ski smoother, filling in the tiny holes of the ski so that there is less (dry) friction involved. However, while that is part of what makes a certain type of wax good, a bigger influence is the creation of a thin layer of water underneath the skis caused by contact with the snow. This thin liquid layer allows an even lower coefficient of friction to be achieved, and has to be taken into consideration when waxing your skis (or snowboard).
Ideally, only a very thin layer of water is created, because too much will create suction due to the fluid nature of the water, while too little will mean there is still too much dry friction. So the relative propensity of the snow to turn into water on contact has to be taken into account in order to create this balance, and this relative propensity is determined largely by temperature, which is why different conditions require different waxes. Colder temperatures make it harder to create a liquid layer, meaning a stiffer, harder wax is needed, because a harder wax will melt more of the contact layer. On the other hand, warmer temperatures work best with a softer wax. For competitive racers, this means that wax is often reapplied before every race in order to get the optimal conditions. However, for the less enthusiastic, a mid-range wax will often work fine.
In case you're every feeling slow on the slopes, take this waxing knowledge into consideration. Soon you'll be zipping around like no one's business.