Fair is foul, and foul is fair 
Hover through the fog and filthy air. (1.1.10–11)

These ominous lines conclude the play’s opening scene, in which three witches meet amidst thunder and lightning before vanishing into “the fog and filthy air.” The foul weather, along with the foreboding presence of the witches in the opening scene, establishes the setting of the play as dark and haunted by evil, supernatural forces. A few scenes later, Macbeth echoes the witches’ paradoxical mantra of “Fair is foul, and foul is fair” when he says, “So foul and fair a day I have not seen.” Throughout much of the play, foul weather and strange, unnatural events reflect the treacherous actions of Macbeth that upset the natural order in the kingdom of Scotland.  

The night has been unruly. Where we lay, 
Our chimneys were blown down and, as they say, 
Lamentings heard i' th' air, strange screams of death, 
And prophesying with accents terrible 
Of dire combustion and confused events 
New hatched to the woeful time. The obscure bird 
Clamored the livelong night. Some say the Earth 
Was feverous and did shake. (2.3.28–35)

In these lines, spoken just before Duncan’s body is discovered, Lennox tells Macbeth about the violent storm that occurred outside the castle on the night of the king’s murder. Powerful winds blew down through people’s chimneys, carrying noises that sounded like “strange screams of death” and people mourning (“lamentings”). In addition, an owl (“the obscure bird”) hoots all night, and the Earth shook like a person with a fever. Lennox describes these events in supernatural terms, implying that the strange storm is a prophecy of terrible events to come. Moments later, a horrified Macduff returns with news of the king’s murder, which seems to confirm a kind of supernatural connection between events in nature and the tragic events of the play.  

Thou seest the heavens, as troubled with man’s act, 
Threatens his bloody stage. By th' clock ’tis day, 
And yet dark night strangles the travelling lamp. 
Is ’t night’s predominance or the day’s shame 
That darkness does the face of Earth entomb 
When living light should kiss it? (2.4.5–10)

After King Duncan’s murder, Ross observes the unnatural daytime darkness, possibly referring to a solar eclipse, yet another example of how the play’s dark setting mirrors its dark events. Ross suggests that the heavens are “troubled” by Duncan’s murder, and he personifies “dark night” as a murderer strangling the sun (“travelling lamp”).  He goes on to characterize darkness as “entombing” the Earth at a time when “living light should kiss it.” Both of these metaphors for untimely darkness bear a strong resemblance to the death of Duncan, who was murdered while traveling and entombed before his time.