Mizzle is a term used in Devon and Cornwall for a combination of fine drenching drizzle or extremely fine rain and thick, heavy saturating mist or fog. While floating or falling the visible particles of coarse, watery vapor might approach the form of light rain. Mizzle is especially thick in upland areas, like its Scottish Highlands counterpart Scotch Mist, and it is particulary associated with a moist tropical maritime airstream.
Mizzle is known for being capable of soaking you in a matter of minutes and the feeling is best described as if one would stand under a Fire Brigade fine nozzle. The word itself derived from the Frisian mizzelen meaning - what a surprise - drizzle. However, a day with mizzle is usually characterised by dull and depressing weather and some sort of permanent twilight, or 'dimpsey' as another good old west country word puts it.