Today is the autumn equinox, which Old English speakers called emniht. Emniht is itself a shortening of the longer form, efennihte, though I am only aware of one instance of the longer form (in an Anglo-Saxon abridgement of De Natura Rerum by the venerable Bede). This is the official shift from the long days and short nights of summer to the approach of winter. From there will be more dark than light, and more night that day, until the solstice, or sunn-stede.