Shunted to the back of the wardrobe during summer months, they only appear when winter is approaching. As days grow shorter, coats become longer. Happiness levels are often reflected by hours of sunlight; the same could be said for inches of overcoat.
It is entirely appropriate that undertakers wear overcoats. Those involved in the corpse-disposal industry need to put on a permanent display of earnest solemnity – nothing achieves this better than an overcoat. You will never see an undertaker without one.
Unsurprisingly, the only other profession to adopt the overcoat as a uniform was the military (from the funeral home to the front line; it seems that wherever death goes, overcoats follow). The Soviet army, veterans of the deep-frozen military excursion, have always been strongest advocates of this gloomy garment. But as the 20th century rolled on and technology advanced, the overcoat, much like the Soviets, became increasingly redundant.
For final proof of the overcoat’s depressing tendencies, look no further than your nearest phrasebook. To ‘put on the wooden overcoat’ is, simply, to die.