Katherine experiences a tropical savanna climate (K�ppen climate classification Aw) with distinct wet and dry seasons. The annual rainfall is 1,132mm and daily temperatures in the wet season typically range from 24� to 35�C, occasionally reaching 40�C, with very high humidity at times especially during the build-up period to the wet season, when the region receives some of the country's most spectacular electrical storms along with vigorous lightning displays. In the dry season, the nights can get quite cool, regularly dropping to 7�C overnight in the middle of the dry season.
Low elevation and frequent rainfall, as well as the town's situation on the banks of a river, means that the area is prone to flooding. A flood on Australia Day in 1998 was particularly destructive. Ex-Tropical Cyclone Les produced between 300 and 400 millimetres of rainfall during a 48 hour period, causing the Katherine River to rise to 21.3 metres and claim the lives of three people.
Floods are not just the only threat the town faces every wet season. Severe thunderstorms and lightning are also familiar dangers every wet season. Large hail to 2.5 cm diameter has also been reported within the area. Katherine is also located in one of the most lightning-struck areas in the southern hemisphere and caution should be taken when outdoors in the summer months
