Relating to rain: rainy
In geology and climatology, a pluvial (Latin pluvilis, from pluvia, "rain") was an extended period of abundant rainfall lasting many thousands of years. Pluvial is also applied to the sediments of these periods (e.g. Lake Bonneville, Lake Lahontan, Lake Manly). The term is especially applied to such periods during the Pleistocene Epoch. A minor, short pluvial may be termed a "subpluvial".
Observation: The Dutch word for umbrella is 'Paraplu'. Could this be an amalgamation of 'Parasol' & 'Pluvial'?