In Ireland, even on an August holiday, our rain is pretty harmless stuff when compared to other places in the world. Listen, for example, to how Fergus Linehan describe Malayan rain in Under The Durian Tree: "Huge purple clouds would appear in the distance trailing curtains of rain. Lightning would crack with a frightening violence, followed by the first peals of thunder. The wind would rise, the approaching storm would be like a whisper, then a swelling roar, then the first drops splattering down, then a torrent, a waterfall of rain that seemed to cover the air in a solid sheet. On and on it would go, interspersed with ear-splitting lightning crashes and thunder like a thousand heavy guns, until gradually it lessened, passed and then was gone . . ."
It must be like that in Cherrapunji. This meteorologically famous little town lies just south of the Himalayas on the Shillong Plateau in the far north-east of India. It has the second highest average annual rainfall in the world: its normal yearly total of 11,430 millimetres is about 10 times that of Ireland and is exceeded only by the 11,680mm average of Mount Waialeale in Hawaii.
And Cherrapunji also holds two more long-standing re cords: between August 1860 and July 1861, it experienced 26,000mm of rain, the most recorded anywhere in a 12month period, and the 9,300mm measured in July 1861 is a global record for a calendar month.
The heavy rain at Cherra punji comes from the monsoon, which sets in each year in early summer. With the coming of spring, the sun moves north of the equator and shines straight down on southern parts of Asia. The continent responds more quickly than the sea to the heat of the sun; and, as the air over land expands and becomes lighter, low pressure develops over the region. Then warm moist air from the ocean, moving anti-clockwise around this low, streams in over India from the south-west. As it is forced to rise over the terrain sloping gently upwards to wards the Himalayas, it brings heavy showers, thunderstorms and torrential rain to Cherra punji and its ilk.
If you would like to know more about the rains of Cherrapunji, now is your chance. This evening's Irish Meteorological Society lecture at 8 p.m. at the Earlsfort Terrace premises of UCD is entitled "Return from Cherra punji - The Wettest Place in the World". The speaker is Prof Greg O'Hare, who spends most of his time at the University of Derby, but must, one assumes, now and then sally forth to foreign parts like Dublin 2 and Cherrapunji.