"All the champions have got to go, I think they want to take photographs..."
--Colin Creevey (GF18)
Garrick Ollivander makes sure the champions’ wands all work properly. They all do. Photos are taken for the Prophet (GF18).
Date: GF18 begins on Sunday morning, the morning after the Hallow'een feast, which dates it as Sunday, 1 November 1994 [Y14]. The Weighing of the Wand takes place on the second Friday after that, which dates the end of the chapter as Friday, 13 November.
Time: We know from GF18 that Double Potions is the class immediately after lunch, that it lasts one-and-a-half hours, and that Harry is retrieved from class for the Weighing of the Wands when there is still an hour left of Potions class. This would seem to put the Weighing of the Wands in the early afternoon - and the event does not seem to take a terribly long time - but Harry goes to dinner after the Weighing and photos are over.