The climate of any country, or in other words, its average weather, by which, again, we mean its temperature, rainfall, and hours of sunshine, as well as the dryness or otherwise of its air, depends upon various circumstances and conditions, but especially upon geographical position, that is to say, upon the nearness of the country to the equator, upon its distance from the sea and its height above sea-level; partly also upon its soil and vegetation. Speaking generally, the nearer we approach the equator the hotter will be the climate, and the nearer to the sea-coast the milder and more equable it will be. The highest temperature in the shade ever yet recorded, however—127° Fahr.—was in the Algerian Sahara, at a spot not even within the tropics; and the greatest cold ever experienced, 90° below zero, Fahr., was at a place in Siberia only just within the arctic circle.
The climate of the British Isles is very greatly influenced by the great ocean current, often called the Gulf Stream, from its supposed source in the Gulf of Mexico, which, impelled by steady winds, carries a constant stream of warm water from the equatorial regions towards the north pole. This current washes the shores of these islands, and it is this circumstance which makes our winters so much milder than those of Labrador, which is no nearer to the pole than we are. Were it not for the Gulf Stream our weather would probably be more severe than that of Newfoundland.
The highest shade temperature ever experienced in Britain was 101° Fahr., at Alton in Hampshire, in July, 1881; and the lowest was 10° below zero, Fahr., at Buxton in Derbyshire, in February, 1895. A temperature of 23° below zero is said to have been measured in Berwickshire, in 1879, but the correctness of the record has been questioned. What is, however, of more importance, is the average temperature for the year, which, for the whole of England, is 48° Fahr.
The sunniest part of England lies, as might be expected, along the south coast, although the south-east and south-west coasts also get more sunshine than inland districts in the same latitude. The sun is above the horizon in this country for more than 4450 hours in the year; but, owing to the frequent presence of clouds, he is not visible for even half that time in any part of the British Isles and the average for the country as a whole is only 1355 hours. The southern coasts sometimes enjoy 2000 hours of bright sunshine in a year, but their average is probably not more than 1700 or 1800 hours, or about five hours a day all the year round. The amount decreases as we go north; while the manufacturing districts of the midland counties, owing to the smoke which so often obscures the sky, get 1200 hours or less. At Manchester in 1907 only 894 hours of sunshine were recorded for the year's total. The sunniest months throughout the country generally are May and June, and the gloomiest month is December.
The Winter Garden at Torquay
The climate of a country, however, depends not only upon the sunshine, but upon the rainfall. The amount of rain that falls in any place varies according to the height of that place above the sea, its distance from the coast, and the configuration of the ground, that is to say, upon its position with respect to valleys, up which moisture-laden air may be driven by the wind, to be compressed and cooled until its moisture falls in rain.
The rainfall varies very much in different parts of England, but the average amount for the whole country is about 33 inches in a year. When we speak of an inch of rain we mean that it would lie an inch deep on a perfectly level piece of ground. Thus, if all the rain that fell in a year stayed on the ground, and did not evaporate, or run away, or sink into the earth, the water would be 33 inches deep all over England at the end of the twelve months. An inch of rain all over an acre of ground weighs rather more than 100 tons. Not only does the rainfall vary in different parts of the country, but it varies in different years. The wettest year on record was 1903, when the rainfall averaged 50 inches for the whole of England; and the driest year was 1887, when it amounted to no more than 24 inches.
The heaviest rainfall in Great Britain is in the mountains round Ben Nevis and Snowdon, in the English Lake District, and in the uplands of Cornwall and Devon. And it may fairly accurately be said that, as we cross England from west to east, the amount of the annual fall steadily decreases, as is shown in the accompanying map. The moisture-laden clouds, driven across the Atlantic by the prevalent S.W. winds, discharge their contents on meeting the cold high lands of western England, which thus act as a sort of umbrella, the driest parts of the country being on the east coast. While the average fall over a considerable part of the west side of it is from 40 to 60 inches, that on the east is no more than from 25 to 30; and round the Wash and in parts of Suffolk and Essex it is under 25 inches. Thus it sometimes happens that when the west of England has rain enough and to spare, the eastern districts are suffering from the want of it. The effect of this difference is shown in a marked degree in the character of the crops. The farms of the rainier west are to a great extent laid down in grass. The drier districts of the east grow more corn, which needs dry weather to ripen it.