'Good evening, Rosmerta, good evening ... forgive me, I'm off to the Hog's Head ... no offence, but I feel like a quieter atmosphere tonight...'
-- Dumbledore, out for a stroll (HBP25)
They leave Hogwarts on foot since it’s not possible to Apparate on Hogwarts grounds and walk through Hogsmeade. They greet Madam Rosmerta by the Three Broomsticks, then walk on to the Hog’s Head before Apparating away.
They leave just as it's getting dark. On June 30, 1997, the sun set at 10:05 PM in Scotland, so they will have been walking through Hogsmeade around 10:30.