A period of quiet, rather settled weather some time in the late autumn or early winter, such as we have recently experienced, is more the norm than the exception.
Sooner or later, almost every year, the normal pattern of eastward-moving depressions is interrupted for a time, as a short-lived anticyclone develops over western and northern Europe; it is a sort of encore that even the most mediocre of summers cannot quite resist, a welcome respite that occurs with sufficient regularity for it to have become a feature of the folklore of many countries.
Indeed there are so many instances of the "old wives' summer", that no matter when the good weather comes along, it can be welcomed as something of an institution.
The ancient Greeks, for example, had their halcyon days, a period of about two weeks centred on the winter solstice, or beginning about December 11th. The story was that the regular spell of quiet, fine weather in the Mediterranean around that time of the year gave the halcyon, a species of kingfisher, the opportunity to build its nest on the rocks among the Greek islands.
It was able to hatch its young before harsh winter conditions made the exercise impossible.
In medieval times such a spell was linked to the nearest date of consequence on the church's calendar.
If, for example, the anticyclone established itself in early autumn, it became "St Michael's Summer", linked to his feast day on September 29th. "All Hallows Summer" was a fine spell coinciding with All Saints' Day on November 1st, while St Martin's Summer was believed to start on his feast day on November 11th. A period of fine weather around this time of year is associated with the feast of Luke, which is today, October 18th, and becomes "St Luke's Summer".
But perhaps the best-known expression for autumnal warmth and sun, albeit not related to any specific date, is "Indian summer".
The term is of relatively recent origin, unknown it seems before the middle of the last century. It relates to the brief spell of warm and pleasant weather which was regularly expected every year by the American Indians, and used by them to prepare for the harsh winters on the Great Plains.
Its traditional character was well captured by the American writer Henry Brooks Adams in a brief description of the peaceful pleasures of advancing years: "The Indian summer of life should be a little sunny and a little sad, like the season, and infinite in wealth and depth of tone - but never hustled."