When conditions out of the ordinary occur, meteorologists blow the dust from their bulky piles of weather data, and with a flourish produce something equally impressive from the archives of generations past.
And there is no doubt that the high temperatures of recent days have been exceeded in this country down the years. But not often. Indisputably, it has been very hot indeed for Ireland.
Temperatures in excess of even 25° are unusual, being experienced on only two or three days in the average summer.
But temperatures in excess of 30° are very rare indeed, and occur perhaps only once or twice in several years, and then only in the midlands. And when we hit the 30s, we are in the record- breaking zone. The highest measure here was 33.3° at Kilkenny Castle on June 26th, 1887, and the highest reached in the 20th century was 32.5° at Boora, Co Offaly, in 1976.
Irish summers are a bit of a lottery. A spell of fine weather occurs over parts of Europe when a high pressure system, temporary extensions of the semi-permanent anticyclone in the vicinity of the Azores, becomes established for a time. In an almost random way, it may develop over central or southern Europe, Scandinavia, Ireland and Britain, or perhaps, as at present, in the middle of the North Atlantic extending over Ireland.
These summer anticyclones bring warm, sunny weather over their area of influence, and fend off rain-bearing North Atlantic depressions.
But other factors contribute to very hot conditions of the kind being experienced here in Ireland. When the weather has been relatively dry for some time, the ground contains very little moisture; no heat is absorbed in evaporation, and therefore more of the sun's radiant energy is available to heat the soil. Very high temperatures are also likely when an anticyclone is positioned in such a way that the air drifting over Ireland has originated over warm, continent- al Europe rather than the ocean.
And thirdly, if the thermal structure of the atmosphere in the high pressure area is such as to discourage, even more than usual in an anticyclone, any vertical movement of the air, this ensures that the heat is trapped in a shallow layer near the ground, rather than being diluted over a much greater volume of the atmosphere. All these factors have contributed to the high temperatures of recent days.
Could this possibly be it? Has the spectre of global warming descended on our Celtic heads? The answer is circumscribed by "ifs" and "maybes".
Heatwaves in themselves are not uncommon. Meteorological records of all kinds, after all, are broken every year somewhere in the world. But weather people will view the current scene in conjunction with other extreme weather events of recent times around the world - floods and droughts, for example, and the occurrence of tornadoes - and it may well reinforce their perception that such extreme weather events have been happening more frequently, and with more severity, of late.
They will recall too, the extraordinary European summer of 2003 and the heatwaves of the past few weeks.
While there is no conclusive scientific link, it is hard to resist the temptation to conclude there must be some connection between the increasing frequency of these extreme weather events and the apparent trend towards hotter European summers, and the inexorable rise in average global temperature in recent decades.
The evolving scenario, as yet, proves nothing, but with a tendency for wetter winters and for hotter, drier summers, it is consistent with predictions of the likely climate pattern in these parts in a warmer world.