Posted November 2nd, 2017, 02:20 PM
According to my "Gentleman's Guide to Etiquette"
"The white dinner jacket's origin on cruises and at tropical resorts speaks to its specific role as a less formal alternative to traditional black tie. It is only appropriate at formal occasions in the tropics year round and in America during the summer season, typically at open-air social gatherings such as country club dances and yacht club parties.
While summer in the southern United States qualifies as being at least subtropical, the same cannot be said for the more temperate northern states and Canada. It is for this reason that numerous experts advise using discretion north of the Mason-Dixon line in order to avoid dressing for effect rather than for the occasion. Indeed, black-tie guests north of the 49th parallel would be wise to heed the example of their British cousins who do not consider the United Kingdom's temperate climate to be appropriate for white formal wear at any time of the year (with the notable exception of Last Night of the Proms).
And if a man is particularly serious about formal convention, a white jacket should never be worn “unless one has a napkin over his arm or a saxophone up to his lips” as Esquire
once put it.
Don't forget that the white jacket is an alternative, not a directive. The black jacket is perfectly acceptable in any season and any locale and actually trumps the formality of the white version"
Or as PG Wodehouse wrote [about the white jacket]
: I assumed it had got into your wardrobe by mistake, sir, or else that it has been placed there by your enemies.
: I will have you know, Jeeves, that I bought this in Cannes!
: And wore it, sir?
: Every night at the Casino. Beautiful women used to try and catch my eye!
: Presumably they thought you were a waiter, sir.