The Tragedy of Macbeth
SCENE I. A desert place.

Thunder and lightning. Enter three Witches

First Witch. When shall we three meet again
In thunder, lightning, or in rain? (1-2)

Here the Witches are not asking about the type of weather in which they should next meet, but when they should meet nextime. Interestingly, these lines follow the punctuation set by an early editor of the play. In Shakespeare's First Folio (1623), we have instead:
When shall we three meet again?
In Thunder, Lightning, or in Rain?
Allan Park Paton, in The tragedy of Macbeth: according to the first folio, explains:
"These lines are thus printed in the Folio of 1623, with a mark of interrogation after each, and, having the author's blotless manuscript before them, we cannot think it possible that Heminge and Condell could have allowed a mistake to occur in the printing of the very first line of the work, and must, therefore, believe that it is the Poet's mark of interrogation, religiously retained through the three succeeding Folios, which stands there. Yet Sir Thomas Hanmer removed it, as if it were a slip on the part of the printer, and in all the modern editions that we are acquainted with, the lines run:
When shall we three meet again
In thunder, lightning, or in rain?
which is a different thing. It seems that Shakespeare could not manage without the two marks of interrogation, odd as they look: that he found it necessary so to arrange the lines, to tell his meaning, which was: "All our meetings are in thunder, lightning, or in rain, when shall our next be sheduled?" not, "We meet sometimes under other elemental circumstances, but when shall we meet again in thunder, lightning, or in rain?" and this opportunity may be taken to note the importance of remembering, as we study the 1623 Folio, that, though occasionally confused through obvious misprinting, we have before us there, Shakespeare's pointing, as well as his words." >

Second Witch. When the hurlyburly's done,
When the battle's lost and won. (1.1.4-5)

After the commotion of the upcoming battle is over (fortelling the next scene).

 

First Witch I come, graymalkin! (1.1.10)

i.e., the witch's pet-name for her familiar spirit.

During the Renaissance it was believed that Satan sent witches malicious spirits to help them carry out their evil deeds. These 'familiars' or 'imps' could appear in animal form. The familiar of the First Witch takes the form of a cat and the familiar of the Second Witch takes the form of a toad (Paddock). The familiar of the Third Witch is not mentioned in the first act but in 4.1, it takes the form of a 'harpy', a nasty creature in Greek mythology with the head and body of a woman and the talons of a bird.

Third Witch


Anon!

i.e., Soon.The Third Witch speaks to her (unnamed) familiar.

Fair is foul, and foul is fair:
Hover through the fog and filthy air. (1.1.12-13)

What the witches do is evil to other beings and vice versa:
Hover inplies that the witches leave the scene flying. >