AS THESE WORDS are being written, the rain is pounding down outside with more ferocity than the drumming of fingers on the keyboard. Met Éireann’s weather forecast has predicted “scattered heavy or thundery showers”. Remove the word ‘scattered’ and the prediction for this Thursday, at least, has been spot on.
There is a strong consensus that the jaunty prediction of the UK’s met office last April that these islands would have a “barbeque summer” this year has lost all its sizzle.
Another Irish summer is coming to an end, and in the common perception, it has been a wet one. There are memories of rain-sodden events during July; the Oxegen festival at Punchestown was deluged, as was the first Bruce Springsteen concert in the RDS. Towards the end of a ceaselessly soaked July, the media widely reported a news release from Budget Travel that families had abandoned the notion of recessionary “staycations” with a surge of last-minute bookings for sun holidays in order to escape the unrelenting rain.
There is some evidence to buttress this. Met Éireann says it was the wettest July for over 50 years in certain parts of Ireland. It was the wettest on record at Valentia in Co Kerry since records began more than a century ago. In the Phoenix Park in Dublin total rainfall of 122 mm was recorded last month, the highest since July 1936. And August has been very little different. The clear skies of the first few days were replaced by more ominous nimbostratus. It has cemented the notion – along with 2007 and 2008 – of continuous rain-saturated summers in Ireland.
BUT HAS ITbeen as bad a summer as all that? And for a country in which the weather is a national obsession, do we know less about the way weather works than we should? In other words, are our knowledge, and our perceptions and expectations of summer, as variable and patchy as the climate?
Strangely, the evidence is that notwithstanding the horribly wet July, it has not been all that bad. “Overall this summer has been close to normal,” says Peter Lennon of Met Éireann’s climate section. He adds the rider that there is still a fortnight of summer left and this week’s heavy rain may yet have a bearing.
The big paradox about the weather in July was that sunshine (which came in the mornings) was above normal, as was the average temperature. So the deluges were interspersed with some good weather, though that seems eclipsed from the common psyche. And there were big variations across the country. Malin Head in Co Donegal experienced a good summer. “It has been relatively dry and sunny there, compared to the rest of the country,” says Lennon.
The index used to compare summers is the Poulter Index, devised by the eminent British meteorologist RM Poulter. His formula is applied to the mean temperature, the total rainfall and the total sunshine during the three months of June, July and August.
The average index for Ireland is 350. The perception that 2007 and 2008 were poor summers is borne out by Poulter which gives a reading of 313 and 306, respectively. But 2006 was a good summer with a reading of 408, though it’s not a summer that springs to mind as memorable. The one that does is 1995, Ireland’s most “Cor-what-a-scorcher” summer. The index then was a vertiginous 434.
Says Lennon: “1995 stands out as being an exceptional summer in terms of heat and sunshine. It was the best summer with one exception. The records from the Valentia station in 1955 show that that year had a better summer in the south west.” But is the heavy rainfall of this summer redolent of more fundamental changes? Prof John Sweeney of NUI, Maynooth, an authority on climate change, says the sequence of three wet summers cannot be taken as indicative of a long-term pattern.
WHY THE WETsummers since 2007? "It is a characteristic of Irish climate," says Prof Sweeney. "Some people suggest that changed conditions in the Pacific associated with El Niño are responsible. We must accept that this is an average summer.
“The intensity of rain has been higher. Climate change models predict more intense rain as climate becomes warmer. Also, the trend has been towards drier summers in the past decade. But we cannot read too much into it.”
Prof Sweeney’s own detailed models for later in the century predict a change towards much drier summers, particularly in the east where precipitation will fall by 25 per cent in July. Conversely, there will be wetter winters in the west. And the frequency of intense rainfall and violent storms will also increase as temperature rises. So, as far as the long-term modelling is concerned, these last three wet summers must be seen as an aberration.
But do people have selective memory of the summer or have mistaken perceptions of what an Irish summer should be? Dr Michael O’Connell of UCD’s school of psychology says the consensus among social psychologists is that people are not rational at processing such information. “People do not compute information like computers. People do not memorise what happened last summer; they regenerate it. They do not work through the summer rationally. Instead, the summer conjures up a series of images and expectations of what a really good summer is like. People are very bad at sampling data from their own memory.”
Dr O’Connell, whose research interests include the study of attitudes, widespread beliefs and inter-group relations, says when people recall events, they are prone to biases and mistakes and are rarely objective. Thus, a sunny period might be forgotten following a prolonged period of rain. Or the perception of a what a good summer is may be influenced by a particularly strong memory of sunny days that excludes the rainy days. “They sample according to whims and biases and shortcuts to get to the answer. They gain ‘good enough’ answers rather than good answers to spare the resources of the brain from being exhausted.”
Incidentally, the Poulter reading for 2009 is 350. Yes, despite our perception of endless rain, it has been an average summer. And the downpour has stopped and the sun is beginning to peep out.
