Like many Americans, I watched parts of the British Open over the weekend and, for those of us caught in hot, humid weather, the cool air in Scotland looked very inviting. While we sat in our air-conditioned homes, perhaps in front of a fan or two, the players and gallery members were festooned in fleece jackets and windbreakers.
Indeed, mid-summer highs in Scotland, Wales, Ireland and western England are generally in the low-mid sixties (F). Prevailing winds are from the southwest, bringing cool, moist air in from the Atlantic; headlands along the coast and highlands throughout the interior force the air to rise, inducing upslope mist and precipitation. Though the United Kingdom stretches across latitudes comparable to southern and central Canada, the Gulf Stream provides a steady supply of relatively warm air and winter, afternoon highs are generally in the forties (F) across the lowlands west of the mountains. On the other hand, atmospheric troughs, dipping across the Northern Atlantic, bring copious rainfall to the region; western lowlands receive about 60 inches each year while mountainous areas receive 120 inches or more.
East of the central highlands, the climate is more Continental. While the classic image of London includes fog and drizzle, that city receives less annual precipitation (about 27 inches) than most urban areas in the central and eastern U.S. (generally 35 inches or more). Heat waves may result from stagnant weather patterns across Western Europe and frigid air may pour southward from the North Sea as polar fronts invade Scandinavia and Eastern Europe; as a result, seasonal temperature variations are much greater across eastern England than in regions along the Atlantic Ocean, which moderates the effects of cold and warm fronts.