The white dinner jacket (please note that it is never pure white, but always winter white or a shade of ivory as natural wool is never pure white) is a classic and accepted option for black tie events if the following conditions are met:
a) The event takes place between May and September. The white dinner jacket is a summer outfit. If you live and/or celebrate in a tropical climate you may ignore this. Likewise, if you live/celebrate in Australia, South Africa, etc. stick to what is considered summer there.
b) The event takes place after 1800 hours (6 o’clock in the evening). Cravatte noire or black tie is an evening dress code. The daytime equivalent would be a stroller.
c) The event or a large part of it, takes place outside. Granted, I consider this point to not be mandatory in certain regions. Having spent time in Georgia, I simply cannot imagine being outside at 7 in the evening in July, wtih 35 degrees Celsius or more and 90 percent humidity.
Please rest assured that a classic white dinner jacket will never look dated. It’s been around for decades, and if you don’t believe me watch “Sabrina” with Humphrey Bogart and Audrey Hepburn 🙂
or here: http://www.vincasa.com/casabla2.jpg (not “Sabrina” but “Casablanca”)
It is worn with black wool trousers with a galon stripe down the side of the legs, white braces to hold up the trousers (black may be visible through the jacket, hence I recommend white), a formal shirt with a turn-down collar, a black silk bow tie (hand tied is always best), and a black silk cummerbund. The best collar is a shawl collar. The gentleman can brighten this up with a flower or a pocket kerchief.
A waistcoat is not really appropriate, because it would be uncomfortable in the heat. The white dinner jacket is a nod to the weather, and thus it is slightly less formal. It is assumed that a softer shirt (when this dress code was devised, formal shirts were so starched that they felt like a board) and a light-coloured jacket would be much more comfortable in the heat. According to my husband who owns dinner suits, a tailcoat and a white dinner jacket this is true. I have to take his word for it as I’ve never tried it personally.
P.S. For a while (1930s) there was also this look, which was inspired by military uniforms:
It is called a Spencer jacket, and a gentleman must have the right build for it (i.e., tall and very slim, with broad shoulders) otherwise it looks very strange.