The climate of the region is semi-arid, being both hot and dry. Weather in the Gilbert catchment, like that throughout north Queensland, is comprised of a wet and dry season. The majority of rain falls over the Gilbert catchment between December and March - on average 775 mm of rain is receive per year, 93% of which falls during the wet season. Rainfall amounts vary substantially from year to year.
Evapotranspiration represents a major loss of water from the system - on average evapotransiration is over 1800 mm per year, more than twice average annual rainfall.
The combination of high rainfall variation between years and high evapotransiration losses should promote the developmemnt of strong drought contingency plans if irrigated agriculture was to expand in the region.
Compared to many agricultural areas in southern Australia there is a lack of in-situ (i.e., on ground) climate data in the north.