The story starts on New Year's Eve with a beheading and culminates one year later on the next New Year's Day. Gawain leaves Camelot on All Saints Day and arrives at Bertilak's castle on Christmas Eve.

What time of year does Sir Gawain and the Green Knight begin?

The story begins at Christmastime at King Arthur's court in Camelot. The knights of the Round Table join Arthur in the holiday celebrations, and Queen Guinevere presides in their midst. The lords and ladies of Camelot have been feasting for fifteen days, and now it is New Year's Day.

What does Gawain do the first time the Green Knight swings at him?

He swings the axe 3 times. The first time he doesn't draw blood because Gawain faithfully gave him (the Green Knight / King in disguise) the 1 kiss on the first hunting day. The second blow is harmless because Gawain faithfully gave him the 2 kisses on the second day.