The idea of climate should be understood as performing important psychological and cultural functions. Climate offers a way of navigating between the human experience of a constantly changing atmosphere and its attendant insecurities, and the need to live with a sense of stability and regularity. This is what Nico Stehr refers to as ‘trust in climate’. People look to the idea of climate to offer an ordered container – a sensory, imaginative, linguistic or numerical repertoire – through which to tame and interpret the unsettling arbitrariness of the restless weather. This container creates Lorraine Daston’s ‘well-ordered foundations without which the world of causes and promises falls apart’. Climate may be defined according to the aggregated statistics of weather in places or as a scientific description of an interacting physical system. Climate may also be apprehended more intuitively, as a tacit idea held in the human mind or in social memory of what the weather of a place ‘should be’ at a certain time of year. But however defined, formally or tacitly, it is the human sense of climate that establishes certain expectations about the atmosphere’s performance. The idea of climate cultivates the possibility of a stable psychological life and of meaningful human action in the world. Put simply, climate allows humans to live culturally with their weather. In this talk I will offer evidence for this argument, drawing upon anthropological, historical and geographical work from around the world. I will also reflect briefly on what the unsettling phenomenon and discourse of climate-change means for the future cultural value of the idea of climate.