In this article, the author intends to define the notion of social atmosphere from the angle of temporality; indeed it is only in the thickness of the present time that the possibility of such or such atmosphere may arise in actuality, as well as its collective perception: the object to catch is fleeting, like the flavour of wine. Consequently, a double epistemological difficulty makes it difficult to describe and define it: on the one hand, this object can only be comprehended in a holitisc approach, because it implies many strata of entangled and instable significations —ranging from aesthetics to politics— so that one may render it; on the other hand, its collective perception, non-verbal more often than not —which does not mean it is unconscious— implies a specific and complex collective cognitive skill, almost immediate: the exchange of efficient signals on one given social stage.