What is sea fret?

Sea fret, also known as coastal fog or haar, is a peculiar phenomenon that occurs on the east coast of the UK[4], particularly in places like Northumberland, Scotland, Scarborough, and along the eastern coast of[4] England. It is caused by warm, moist air passing over the cold surface of the North Sea[4], leading to the condensation of moisture and the formation of fog. This fog can reduce visibility and disorient people, making it potentially dangerous, especially for activities like shipping and oil platforms[4]. Sea fret typically occurs in the spring and summer months when[1] the sea stays relatively cold[1], and can be blown over the coast and inland areas by light winds. It can persist for several days[2] if winds continue blowing east[2] or if land temperatures aren't high enough. The sudden nature of this weather can cause danger due to reduced visibility, and it is typically burned away by sunshine. Overall, sea fret is a cold sea fog[3] that significantly impacts the east coast of the UK, with variations of the term in Scots and northern English[3] such as har, hare, harl, harr, and hoar. Its origin is related to Middle Dutch haren[3], referring to a cold, sharp wind.