What to wear to Bonnaroo: Manchester sits at 31°C (88°F) by day and 19°C (66°F) at night in June, on open field, with a high chance of rain. That means loose natural fabrics and real sun protection, waterproof boots, and a bag small enough for the gate rules. The crowd leans hippie, camping and boho, so anything that survives the day reads as right.
Men's festival dressing at Bonnaroo comes down to three decisions: how much you can take off when it hits 31°C (88°F), what you put back on at 19°C (66°F), and whether your shoes can take open field for 4 days.
The dominant aesthetics at Bonnaroo are hippie, camp-practical, boho and alternative. 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 open field without you having to protect it.
What people actually wear: as little fabric as the venue allows, in natural fibres, with a bag small enough to forget about; wellies or waterproof boots on almost everyone by day two; the same jacket every day, because it lives in the tent and does everything.