A three season tent can be a great option for those who plan to camp only in the spring, summer, and fall, and in most cases, it will suit a camper just fine. Winter camping often requires some extra protection, however, and a four season tent can offer that. As the name suggests, it can be used in all four seasons and has a number of features that makes it more comfortable than a traditional tent for winter camping. It has heavier poles to withstand the additional weight that may come with heavy snow or ice, and more poles to create a more even distribution for the roof and prevent chances of sagging under snow.
A four season tent typically has a distinctive tubular design with a very low profile. For those who do not go camping often, or do not camp in extremely cold weather, these tents can be seen in pictures of camps on Mount Everest and other high-altitude peaks. In that regard, they are often referred to as mountaineering tents. Ironically, this type of tent may be less adept at handling other seasons than a three season tent, simply because it is designed for very cold winter camping conditions. In many cases, the tents can be too hot or too heavy to make a good camping option in warmer months.
Manufacturers, however, have worked to make their products more desirable during other times of the year as well. Ventilation is usually the key to making this tent bearable at times of the year other than winter since, if the air flow through the structure can be improved, it will make the stay much more comfortable. Some manufacturers are also using very advanced materials to make the tent lighter but still offer as much, or nearly as much, winter protection. While this increases the cost of the tent, it also makes it more versatile.
In addition, some tents are convertible from three seasons to four seasons by adding poles and panels. Though these tents may not be quite as efficient as a true four season tent, they will do a good job of protecting campers in many winter weather situations.