What to wear to Sonic Bloom: Rye sits at 27°C (81°F) by day and 10°C (50°F) at night in June, on mountain, with a moderate chance of rain. That means a light base with one warm layer you can carry, broken-in boots or sturdy trainers, and a bag small enough for the gate rules. The crowd leans psy, costume and camping, so a full costume is the norm rather than the exception.
Men's festival dressing at Sonic Bloom comes down to three decisions: how much you can take off when it hits 27°C (81°F), what you put back on at 10°C (50°F), and whether your shoes can take mountain for 4 days.
The dominant aesthetics at Sonic Bloom are psytrance, full costume, camp-practical and fantasy. 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.
This is a costume festival, and that changes the maths: turning up in normal clothes is the conspicuous choice. Budget for one full look rather than three half-hearted ones, and make sure you can walk, dance and queue in it for eight hours.
What people actually wear: one good layer over a light base, because the temperature halves after sunset; the same jacket every day, because it lives in the tent and does everything.