Craigavon vies with Donaghadee for the honour of being the driest area in Northern Ireland. Here the average annual rainfall is slightly over 30 inches, while at Donaghadee it is slightly under 30 inches.
The late Mr. Lynas (father of the late Mr. Alfred Lynas of Edenderry) kept careful records at Moyallon House for many years - especially between 1905 and 1923. These have been carefully preserved by Mr. John Richardson of Bessbrook, who kindly gave me a copy.
In the fifteen consecutive years from 1905-1919 the average annual rainfall was exactly 31 inches. The wettest year during that period was 1908 with 35.07 inches, while the driest year was 1911 with only 27.01 inches.
The year 1923 was a particularly wet year with 40.08 inches and the February of that year was the wettest month recorded in Moyallon with 6.39 inches of rain. Rainfall was recorded on 24 of its 28 days.
August of that same year was a very wet month with 5.76 inches. I remember that very wet month well as most of the meadows were so badly flooded thousands of acres of hay could not be mown. Those who did manage to cut the hay in the boglands had to watch it rot in waterlogged meadows.
On this fairly broad basis, August can be relied upon to give the heaviest rainfall followed closely by May and June.
One inch of rain is equivalent to around 100 tons of water per acre; so a little calculation shows that each acre of ground in this district receives three thousand tons per annum; or in other words almost two million tons per square mile.
If we go to the heart of the Sperrin Mountains, to parts of County Fermanagh or to our local Mourne Mountains we can have twice as much rain as in Craigavon. Is it any wonder then that the little River Bann has a great struggle sometimes to carry all our surplus water to Lough Neagh on its way to the Atlantic Ocean?