Rainfall

Rainfall, the amount of rain that falls at a particular spot or over a certain area in a given time. It is generally stated in inches, being collected in a rain-gauge (q.v.), and allowance being made for evaporation. It is usual to take an average of the total falls each year for a term of years, but a more accurate conception of atmospheric moisture will be obtained if this average is supplemented by a record of the average number of rainy days or by monthly averages. Most of England has an annual rainfall of less than 40 inches, Huntingdonshire having only about 21 inches. Most of Ireland has more than 40 inches; but no part more than 76 inches; whilst in Scotland the highest average is 128, and at Seathwaite, in the English Lake district, the average is 146 inches. The highest recorded annual average in the world is 493 inches at Chirrapunji, on the Khasi Hills, in Lower Bengal. On five successive days 30 inches each day has been recorded at this station, whilst 7 inches is the highest on record for one day in Great Britain.