It opens
空山新雨后,
天气晚来秋。
明月松间照,
清泉石上流。 'In the empty hills after fresh rain, the evening air turns to autumn. The bright moon shines between the pines; a clear spring flows over the stones.'
暝 means dusk, and
山居 is the poet's life at his country estate at Wangchuan, in the hills outside Chang'an.