My feet are more comfortable in both hot and cold weather riding. In fact, I noticed that my feet actually felt cooler when riding, even in mid-summer high temperatures.

Initially, it would seem counterintuitive that a waterproof motorcylce boot will allow your feet to feel cooler in hot temperature riding when compared say, to the same model boot without waterproofing. But the opposite is true. And when we think about it, it makes sense.

On average, our feet give off a lot of humidity (ie moisture vapor). In hotter temperatures, this humidity increases.

A good quality, breathable and waterproof motorcycle boot (ie Gore Tex or other quality breathable liner) will allow this humidity to transfer off your foot and through the Gore Tex liner and then through the leather.

How does this work? The heat generated by your foot will help evaporate the moisture. This evaporated moisture will then go through the permeable membrane (ie Gore Tex) and finally to the leather. The leather liner absorbs the moisture and evaporates it to atmosphere. So in effect, you have evaporative cooling of your boot as well as evaporative cooling of your foot inside the boot. This explains to me why my feet feel cool when riding in hot weather and wearing breathable Gore Tex waterproof motorcycle riding boots.

In order to maximize this, it's best to wear wicking-type socks. In fact wearing wicking type socks during most activities is often a good idea. A cotton sock will absorb humidity and retain it. This slows the flow of humidity through the process ie Gore Tex and then leather. A wicking-type of sock will wick humidity from the foot and more easily transfer it to the Gore Tex membrane.

What about cold weather riding?

I've worn my Gore Tex Kalahari BMW GS boots in temperatures close to 32F (0C) for sustained periods (ie 12 hours or more, night riding). Cold feet have not been a problem for me.

Though the same principles are at play as when riding in hot temperature, some variables change. For example, your feet will generate much lower levels of humidity and sweat when exposed to cold ambient temperatures. And so there will be lower evaporative cooling.

One reason for this is that you are not generating any activity-based heat while sitting motionless on a motorcycle. Any moisture generated by your feet will likewise be evaporated. But the trade-off here is that a non-breathable motorcycle boot will have that moisture saturate your socks and boots. You will lose more body heat through conduction to the cold boot.

In extremely cold weather riding, say at temperatures lower than 32F (0C), I would probably wear some rubber slip-ons over my boots. This would cut down heat loss by both conduction and evaporative cooling.

For the above process to function as intended, permeability must be present at each stage. This includes the Gore Tex membrane as well as the leather.