What to wear to When We Were Young: Las Vegas sits at 26°C (79°F) by day and 14°C (57°F) at night in October, on arena grounds, with a low chance of rain. That means a light base with one warm layer you can carry, cushioned trainers or a low boot, and a bag small enough for the gate rules. The crowd leans punk, alt and goth, so anything that survives the day reads as right.
Men's festival dressing at When We Were Young comes down to three decisions: how much you can take off when it hits 26°C (79°F), what you put back on at 14°C (57°F), and whether your shoes can take arena grounds for 1 day.
The dominant aesthetics at When We Were Young are punk, alternative, gothic and Y2K revival. That is the visual language of the site, the stages, the merch, the crowd photos, and outfits that speak it look intentional rather than borrowed.
There is no enforced dress code. What the crowd rewards is a look that survives 1 day of arena grounds without you having to protect it.
What people actually wear: one good layer over a light base, because the temperature halves after sunset.