Over the centuries the equinoxes have acquired an unsavoury reputation for very violent storms. The notion of "equinoctial gales" has it that very strong winds are much more frequent in late March and late September than at other times of year. But this is patently not so: statistics show that gales in the north Atlantic are most frequent in January and December.
At Malin Head, for example, the average number of days with gale-force winds increases from one in August to nearly four in September, but then continues to climb gradually through the remainder of the autumn to reach 10 in December.
What the statistics do tell us, however, is that there is an abrupt increase in the average frequency of high winds during the second half of September. It is not uncommon, therefore, for late September to provide the first real gale of the season, and this may account to some extent for the "guilt by association" suffered by the equinox.
Another factor also has enhanced the reputation of the autumn equinox as a very windy period. Long after the winds of a Caribbean hurricane have died away, a quantity of unusually warm and very moist air frequently survives, concentrated into a relatively small region of the upper atmosphere to be carried northwards into mid-Atlantic.
If this warm humid air is absorbed into the circulation of an ordinary north Atlantic depression, it may add enough energy to cause a dramatic intensification of the low.
Some of our worst September gales over the years have had their origins in this kind of process. Although the storms containing the warm, humid residues of Hurricanes Isodore and Gustav in September 1990 tracked well north of Ireland, they did their bit to perpetuate the equinoctial myth.
But the event that we recall as Hurricane Debbie, which arrived on our shores 37 years ago today on September 16th, 1961, is that which is by far the best remembered.
Debbie had been born as a hurricane in the balmy waters of the Caribbean some five or six days previously. Its intensity abated somewhat as it turned northwards over the colder waters of the north Atlantic, but by the time the storm reached Ireland it had acquired a new lease of life.
As it passed near the northwest coast of Ireland on its way north-eastwards, Debbie caused great damage in the western half of the country, bringing winds with gusts in excess of 100 miles per hour.
At many places in this country, the record for the highest wind-speed ever recorded was established on this day 37 years ago.