Why one carry-on works across two climates The real problem is volume, not temperature A traveller leaving Oslo at 2°C and landing in Athens at 28°C does not need two wardrobes. The traveller needs a small number of garments that handle different jobs: insulation at the airport, sun protection outdoors, and quick-drying layers during transit. The mistake is packing one complete outfit for every forecast. That approach adds shoes, duplicate tops, and bulky coats faster than most carry-on bags can hold them. The best one-bag system separates climate protection from fashion. Your base layer manages sweat, your middle layer adds…