We're frequently told by purveyors of very short, and therefore unpractically proportioned, overcoats (ie any formal coat that finishes above the knee) that the abbreviated length is informed by the advent of central heating and the fact that men don't spend much time out in the elements anymore.
We suspect it's got more to do with the cost savings afforded by using 25 per cent less fabric per coat, but either way a more elegant answer is to wear a lightweight coat on ays when you only need modest protection against the weather, and to wear a proper winter coat when it's really cold.
From left: the obscurely hip, made-in-Britain option, £90, by Lavenham. The more daring Italian option, £600, by Canali. The versatile option, because it's quite thick, £95, by French Connection. the classic option, never wrong, £80, by Barbour