Is this weather really normal?
THIS MIGHT seem like a dire summer without compare, delivering floods of rain and short rations of sun. Yet the weather statistics for summer 2012 are likely to show it was not out of the ordinary and was within the realms of “normal”.
The jet stream, high altitude winds that help dictate weather on the ground, has turned its face against us. Like a conveyor belt, it has dragged low pressure air over Ireland for months, with plenty of rain and wind.
Yet the reason the summer seems so bad is not only related to the weather and may have more to do with our great expectations of what an Irish summer should be.
“The expectations that people have are a little bit unrealistic,” says Séamus Walsh, senior climatologist at Met Éireann. “One or two times a decade you might get a dry, warm, sunny summer,” he says.
“People have an expectation of a Mediterranean summer every year but we don’t get them. We feel we should expect such weather but it doesn’t work like that. We never learn.”
There is plenty of evidence that summer is drawing to a close, not least the “back to school” advertising. Actual summer persists for another eight days however and the final seasonal weather statistics won’t be ready before then, says Walsh.
The current five-day forecast suggests more of the same with several more soakings of rain before the end of the month, but so far the season “is within the range of what we can get”, he says.
The latest figures with a week before autumn still to go show the midlands, south and east have seen rain at about 200 per cent of the 30-year average. Western coastal areas are running at between 100 and 150 per cent of the long-term average.
Average sunshine is also down, between 70 and 90 per cent of typical, he said. Average temperatures have also been depressed with summer season averages running at a half to one degree below average.
If the rain predicted to hit later in the week materialises then some weather stations may see seasonal records set, Walsh suggests. But 2012 was not extrordinary and may not be as wet as the summer of 2008.
In that year June delivered 150 to 200 per cent of average rainfall and between 150 and 300 per cent in July. August 2008 was also wet, with 200 per cent of average rainfall.
He acknowledges however that the statistics can be misleading given that a single storm or heavy thunder shower might deliver a month’s rain in a matter of hours. “You can quite easily get 200 per cent of average rainfall,” he says.