Henley has a dress code nobody hands you in writing. You are expected to already know it.

The Stewards' Enclosure asks for a jacket and tie regardless of the heat, so the cloth has to manage what the weather won't.

A club tie or a regimental stripe reads as fluent here. A boating blazer earns its keep for one week a year and nowhere else.

The river doesn't care how you're dressed. Everyone else does.