Ah, the white gentleman's dinner jacket. When exactly is it worn? Originally, white jackets were adopted in more tropical climes where the traditional dark and heavier weight fabrics were too uncomfortable to bear in the heat. Also, it's really not white, more of an ivory color. Still, it's mostly accepted that a white dinner jacket can be worn in the warmer summer months, up to Labor Day. The Brits refuse to wear it at all. I think they are missing out on something wonderful.
Personally, I think they are very sleek and elegant, although tend to agree about the warm weather wearing. It just fits with the tropics.
One can not deny the sophistication of Bogart in his white DJ. From the movie Casablanca.
This photograph I am particularly fond of. Two gents in white DJ's with a bride sitting in a vintage car. The chap on the right in the cowboy hat is my dad, and that was one of his automobiles. My dad was cool. It seems every gent has a bit of Bogie in them when they don a white DJ. No exception here.