Fell walkers of his generation would wear tweed and carry a cotton mac in case of wind and rain. Here AW has sketched himself on Lanthwaite Hill, overlooking Crummock Water, wearing his trusty Harris tweed jacket (carefully labelled as such). Naturally he has a pipe clamped firmly in his jaw.
Tweed can be worn in all weathers; it's warm, breathable, shower-proof, robust and you don't rustle like a paper bag. Properly layered., it can be used on most (cooler) days in the UK.
[Post edited to add a bottle of Thwaites Wainwright beer].
Italian men would sell their mothers to achieve this level of genuine sprezzatura:
