I went to one a couple of years ago. It was a scorching summer day which was better than rain as there is wasn’t much cover. Most of the women wore summer frocks and some had jackets (like wedding guests but not MoB). Some wore hats or fascinators, I wore a hat I bought from a charity shop because of the sun), but not all. I’d say about 30% didn’t wear anything on their head.
The first aid tent did a roaring trade in dressing foot blisters and lots of women ended up barefoot with plasters on their feet, carrying their unsuitable shoes! I wore some poshish wedges from Pavers and my feet were really comfy.
The food was lovely, fresh sandwiches, tiny little bagels, little cakes, ice cream. And you could go back for a second helping if you wanted.
Massive queue to get in, be warned.
I had a lovely day, even though i’m not really a royalist, it still felt very special. Got a handshake, which was unexpected!