I'm looking to buy a new trekking tent, a good quality one, e.g. Hilleberg, Fjällräven, Vaude, etc. At Vaude they categorise tents in 2, 3, 4, or 5-season. What's the difference between a 4- and a 5-season tent? I know 4 seasons (although the Sami have 8 seasons) and have camped in all of them in a sub-Arctic mountain climate (northern Fennoscandinavia) with my Wechsel Rafter tent, which now starts to leak water after 6 years.
How important is the "seasonality" of a tent? In my understanding, a tent protects against wind and precipitation, which occur in any season; a sleeping bag protects against the cold. Then why are tents sorted by seasons? What does a 5-season tent have that a 4-season tent does not, how does this differ from a 3-season tent, etc.? And what is the 5th season?