By Philip Eden

We all know the Lake District is wet. The Wordsworths knew it; Dorothy's journals are replete with descriptions of sodden days and rainy evenings. And to Coleridge is attributed the remark, "Summer has set in with its usual severity."

But until the 1840s nobody had any inkling just how wet. It was then that the first rain-gauges were established in the region, and we have now completed 160 years of daily rainfall measurements in Borrowdale which we now know to be the wettest inhabited part of England.

In the early 19th century, theories about rainfall in mountainous areas were, to say the least, confused. It was generally believed that the quantity of rain diminished with altitude: a logical idea when one considers that temperature decreases with height above sea-level, and that cold air holds less moisture than warm air. Scientists of the day struggled and failed to reconcile this concept with the fact that winter was normally a much wetter season than the summer.

The first serious attempt to measure rainfall in the Cumbrian hills was organised by a certain John Fletcher Miller who was then a thirty-something gentleman scientist who lived in Whitehaven. He had installed a rain-gauge in his own garden on the Cumbrian coast at the age of 17, in 1833, and ten years later he established a network of gauges over the southwestern corner of the Lake District. One of these was at Seathwaite - the highest hamlet in Borrowdale - where readings were taken by Mr Dixon, the manager of the nearby graphite mine. Miller must have been astonished when he came to add up the figures at the end of the first full year of observations - 1845 - for Seathwaite's total was 152 inches (3800mm), compared with just below 50 inches (1270mm) at Whitehaven.

London-based meteorologists first scoffed at the figures. It was widely believed at that time that it was not possible to have more than 100 inches (2540mm) of rain outside the tropics. But the extraordinary numbers continued to appear, usually between 100 and 160 inches (2540 and 4060mm) per year, and averaging 129 inches (3277mm).

Subsequent investigations showed that even more rain fell on the north-facing slope of the Scafell massif, up to an altitude of about 2000ft (600m), with an annual average of 185 inches (4700mm) at Sprinkling Tarn. The higher-level gauges have long since been "rationalised" out of existence, but the Seathwaite record continues, now under the auspices of the Environment Agency.

© Philip Eden