What to wear to Øya Festival: Oslo sits at 20°C (68°F) by day and 13°C (55°F) at night in August, on city park, with a high 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 indie, streetwear and alt, so anything that survives the day reads as right.
Women's outfits at Øya Festival have to clear the same three hurdles as everyone else's. 20°C (68°F) by day, 13°C (55°F) at night, city park underfoot, with more options for solving them.
The dominant aesthetics at Øya Festival are indie, streetwear, alternative and quiet elegance. 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 4 days of city park without you having to protect it.
What people actually wear: one good layer over a light base, because the temperature halves after sunset.