Given how far north it lies (it's on the same latitude as Labrador in Canada), you might expect Edinburgh's climate to be colder than it is, but the Gulf Stream (a warm Atlantic current) keeps the prevailing westerly winds pleasantly mild. May, June and September are generally the best months for dry, sunny weather, but you can expect rain at any time. The weather changes quickly, too - a rainy morning can often be followed by a sunny afternoon. A distinctive feature of Edinburgh's weather is the 'haar', a dense, chilly fog that often blows in from the North Sea when the wind is in the east. You can usually escape it by heading just a few miles inland.