That our weather is subject to cycles of a certain kind is obvious. Average wind, temperature and rainfall all vary with the time of day, and the four seasons comprise a cycle which recurs with quite monotonous regularity. But people sometimes look for evidence of a cyclical variation in the weather over a much longer period; if, as Shakespeare said: "There is a tide in the affairs of men", could there not also be a similar rhythmic variation of the elements?
In the 15th century, for example, the philosopher Francis Bacon announced his discovery of what came to be known as "Bacon's Prime". He described it in 1620 in On the Vicissitudes of Things: "They say it is observed in the Low Countries that every five and thirty years the same kind and sort of weather comes about again; as great frosts, great wet, great droughts, warm winters, summers with little heat and the like; and they call it the `Prime'; it is a thing I mention because computing backwards I have found some concurrence."
This concurrence was avidly pursued. Indeed to meteorologists in succeeding centuries, Bacon's Prime became a kind of Holy Grail - widely believed in, never found, but ever sought.
In more recent times, some meteorologists drew attention to the fact that frequent and destructive gales were a feature of the 1690s, the 1790s and the 1890s.
This pattern led them to suggest that there might be a 100year cycle in storminess resulting in a peak at the end of each century.
They were delighted with the very boisterous conditions common during the 1990s, and indeed still with us, since these reinforced their cyclic arguments.
Another alleged cycle relates to claims by some watchers of the weather that since around 1800 or thereabouts, very cold winters have appeared consistently in these parts every 22 or 23 years.
They point to the most recent in the series as being the icy winters of 1940, 1941 and 1942, the severe conditions of 1962 and 1963, and the snowy winters of 1985, 1986 and 1987.
Extrapolating the sequence, the "cyclists", if one may call them that, predict an interruption of the current trend for very mild winters around 2007 or 2008, and a temporary reversion to very harsh conditions - likely to be, they say, the most severe experienced for a generation.
Some might say, of course - as the same Francis Bacon of the Prime remarked - Quod mavult homo verum esse, id potius credit - "What a man would like to be the truth, that doth he more readily believe." But we shall have to wait and see.