November delivers the coup de grace to a dying autumn. It is a period during which the pleasant aftertaste of a fine summer can sometimes be detected in brief intervals of hazy sunshine. The roughness of the coming winter, however, intrudes with increasing arrogance as the month matures, and what is left of the autumn foliage is often overwhelmed by the dark, dank, clammy fogs of the closing year.
The frequency of fogs is explained by the fact that atmosphere is still warm enough to hold a fair amount of moisture, and when conditions otherwise are right, the long cold nights allow plenty of time for the temperature of the air near the ground to fall below its condensation point.
The fogs are persistent because the morning sun lacks the energy needed to disperse them, and so they often stay all day.
A mere two hours of daily sunshine is the November norm - in contrast, for example, to the six or seven typical of the average day in June. The maximum temperature on a typical day is about 10 or 11degrees C; at the other extreme, the temperature in inland areas drops below zero, on average, on six or eight days during the month, and the temperature at grass level is below zero on over a third of November mornings. Although not the windiest month of the year - that doubtful honour goes ex aequo to January and December - November is not far behind in this respect.
Many years ago, the Dublin physician and amateur meteorologist John Rutty was of the view that there was a purpose to this elementary cocktail.
Writing in 1772, he said of November: "It has more fogs and a good deal more storms and frosts than October - and for a very obvious reason, viz, that whilst the Sea and Earth are ever teaming with vapours, the ever declining Sun hath not the power to dissipate them, and did not those storms proper to this month by the gracious and wise disposition of Providence, perform this work, undoubtedly the ill effects of the stagnating vapours would be felt much more than in fact they are."
But in Apollo Anglicanus written a century before, Richard Saunders across the channel found it much more difficult to see the bright side. Of November, he wrote: "In this month Melancholy much increaseth and Blood decreaseth. Eggs and honey now are very wholesome, salt powdered meats are good, but this is the most perilous time of year to bath in. And it is good to vomit sometimes."