From AMS Glossary
A stormy, rain-bringing wind from the southwest or south-southwest in Hawaii.
It blows about five times a year on the southwest slopes that are in the lee of the prevailing northeast trade winds. Kona is the Polynesian word for "leeward." It is associated with a southward or a southeastward swing of the Aleutian low and the passage of a secondary depression (kona cyclone) from northwest to southeast, north of the islands.