a cold, easterly wind; a gentle easterly breeze; a sea mist. This very useful word is technically well explained in these quotations:
In the months of April and May, easterly winds, commonly called Haars, usually blow with great violence, especially in the afternoons (William Nimmo A General History of Stirlingshire 1777).
The easterly har, a sea breeze so called by fishermen, which in the Moray Frith during the summer months and first month of autumn, commonly comes on after ten o’clock a.m. and fails at four o’clock p.m. had now set in (Hugh Miller Letters on the Herring Fishery 1829).
The haar, however, does not extend itself a great way into the country, for, by the time it has reached the distance of perhaps twenty or thirty miles from the shore, it is generally dissipated by the greater heat of the interior land (James Grierson Delineations of St Andrews 1807).
[The North Sea] being five degrees warmer in summer, than the Atlantic, a copious evaporation takes place, throughout its extent, which produces the eastern haars (as they are called) or thick mists, which are seen, at a certain period of the day, to arise from the sea (John Sinclair General Report of the Agricultural State and Political Circumstances of Scotland 1814).
However, none of the above quite gives the sense of chill with which even a summer haar can penetrate to your marrow. Add to this the smoky pollution of Edinburgh chimneys, which gave Edinburgh its nickname of ‘Auld Reekie’, in the nineteenth century, and it is easy to sympathise with John Wilson (Christopher North) in Noctes Ambrosianae (1827): But it’s just your ain vile, vapoury, thick, dull, yellow, brown, … easterly haur o’ Embro’ that gies me the rheumatics.
Haar is more poetically described by Gilbert Rae in ’Tween Clyde and Tweed (1919): Within a martyr’s grave, Ower whilk the white haur dreeps.