Plaissan (French pronunciation: [plesɑ̃]) is a commune in the Hérault department in the Occitanie region in southern France.

Exposed to a Mediterranean climate, Plaissan is drained by the Dardaillon, the Rouvièges stream, and two other rivers.

The municipality has a remarkable natural heritage, which includes an area of ecological, fauna, and floristic interest.

Climate projections for 2050, based on various greenhouse gas emission scenarios, are available on a dedicated website published by Météo-France in November 2022.

[5][6][7] The Inventory of Natural Areas of Ecological, Fauna, and Floristic Interest (ZNIEFF) aims to encompass the most ecologically significant areas, primarily to enhance understanding of the national natural heritage and to provide regional planners with a tool to integrate environmental considerations into their decision-making processes.