The Weatherly 620 is a 1970s American agricultural monoplane designed and built as an improved variant of the Weatherly 201 by the Weatherly Aircraft Company of McClellan, California.
The Weatherley 620 is an all-metal single-seat low-wing cantilever monoplane with a conventional landing gear with a tailwheel. Examples have been fitted with a Pratt & Whitney R-985 radial engine, and PT6A or TPE331 turboprop engine, driving a three-bladed tractor propeller. In the forward fuselage, the aircraft has a either a 355 US gallon hopper or a 320 US gallon hopper that feeds an agricultural dispersal system. Most pilots that fly the weatherly aircraft, prefer the 320 gallon hopper aircraft.