9. Weather and Climate. Temperature. Rainfall. Winds.
The climate of a county depends on a good many things, its latitude, its height above sea-level, its proximity to the sea, the prevailing winds, and especially as regards Scotland whether it is situated on the east coast or on the west. The latitude of Great Britain if the country were not surrounded by the sea would entitle it to a temperature only comparable to that of Greenland but its proximity to the Atlantic redeems it from such a fate. The Atlantic is 3° warmer than the air and the fact that the prevailing winds are westerly or south-westerly helps to raise the mean temperature of the western counties higher than that of those on the east. The North Sea is only 1° warmer than the air so that its influence is less marked.
Still, considering its latitude (57°-57° 40’), Aberdeenshire enjoys a comparatively moderate climate. It is neither very rigorous in winter nor very warm in
Rainfall Map of Scotland. (After Dr H. R. Mill)
Rainfall Map of Scotland. (After Dr H. R. Mill)
summer. Of course in a large county a distinction must be drawn between the coast temperature and that of the high lying districts such as Braemar. The fringe round the coast is in the summer less warm than the inland parts, a result due to the coolness of the enclosing sea, but in the winter this state of affairs is reversed and the uplands are held in the grip of a hard frost while the coast-side has little or none.
The mean temperature of Scotland is 47°, while Aberdeen has 46°·4 and Peterhead 46°·8. That of Braemar, the most westerly station in the county, though in reality very little lower, is arrived at by entirely different figures; the temperature being much higher during July, August and September, but lower in December, January and February. Braemar is 1114 feet above sea-level and since there is a regular and uniform decline in temperature to the extent of 1° for every 270 feet above the sea, the temperature of this hill-station should be low. As a matter of fact, from June to September it is only 9° and in October 7°·5 below that of London. Yet its maximum is 10° higher than is recorded at Aberdeen, only in winter its minimum is 20° lower than the minimum of the coast.
Braemar and Peterhead as lying at the two extremes of the county may be compared. Peterhead receives the uninterrupted sweep of the easterly breezes, for it has no shelter or protection either of forests or mountains. The impression a visitor takes is that Peterhead is an exceptionally cold place. As a fact, its mean winter temperature is above the average for Scotland, but the lack of shelter and the constant motion of the air give an impression ofcoldness. In the summer and autumn its mean falls below that of Scotland. It is therefore less cold in the cold months and less warm in the warm months than Braemar and has a seasonal variation of only 16°·3 between winter and summer, whereas Edinburgh has a range of 21° and London of 26°.
Inverey near Braemar
Inverey near Braemar
The rainfall over the whole county is also moderate, ranging from less than 25 inches at Peterhead—the driest part of the area—to 40 inches at Braemar, and 32 at Aberdeen. This is a small rainfall compared with 60 or 70 inches on parts of the west coast. The driest months in Aberdeenshire are April and May, and generally speaking less rain falls in the early half of the year when the temperature is rising than in the later half when the temperature is on the decline. Two inches is about the average for each month from February to June, but October, November and December are each over three inches. The most of the rainfall of Scotland comes from the west and south. This explains why the west coast is so much wetter than the east. The westerly winds from the Atlantic, laden with moisture, strike upon the high lands of the west, but exhaust themselves before they reach the watershed and, having precipitated their moisture between that and the coast, they reach the east coast comparatively dry. Braemar just under the watershed is relatively dry. Its situation as an elevated valley, 1114 feet above sea-level and surrounded on three sides by hills of from three to four thousand feet, and the fact that it is 60 miles from the sea combine to make it one of the most bracing places and give it one of the finest summer climates in the British Isles.This sufficiently accounts for its popularity as a health resort. May is its driest month, October its wettest.
Easterly winds bring rain to the coast, but as a rule the rain extends no further inland than 20 miles. Easterly winds prevail during March, April and May, which make this season the most trying part of the year for weakly people. In summer the winds are often northerly, but the prevailing winds of the year, active for 37 per cent. of the 365 days or little less than half, are west and south-west. East winds bring fog, and this is most prevalent in the early summer, June being perhaps the worst month. The greatest drawback to the climate from an agriculturist’s point of view is the lateness of the spring. The summer being short, a late spring means a late harvest, which is invariably unsatisfactory.
The low rainfall of the county is favourable to sunshine. Aberdeen has 1400 hours of sunshine during the year in spite of fogs and east winds; the more inland parts being beyond the reach of sea-fog have an even better record.
The great objection—an objection taken by folks who have spent part of their life in South Africa or Canada—is the variableness of the climate from day to day. There is not here any fixity for continued periods of weather such as obtains in these countries. The chief factor in this variability is our insular position on the eastern side of the Atlantic. When, on rare occasions, as sometimes happens in June or in September, the atmosphere is settled, Aberdeenshire enjoys for a few weeks weather of the most salubrious and delightful kind.