Etymology
Attested since the late 17th century, alongside Scots haar (“cold easterly wind; misty wind; cold fog or mist”).
Perhaps ultimately from Middle Dutch hare (“cold wind”) or a related Low German word; compare Dutch harig (“windy; foggy, misty”), Saterland Frisian harig (“misty”).
Alternatively, perhaps simply a northern English or Scottish variant of hoar, or a borrowing of Old Norse hárr (“hoary”).