The events affect these routes:

Toronto Transit Commission — 6 Bay.

York Region Transit — 54 Bayview North; 56 Gorham - Eagle.

The Saturday, December 20 event affecting transit is: Cavalcade of Lights.

The Sunday, December 21, Monday, December 22, Tuesday, December 23 and Wednesday, December 24 event affecting transit is: Live Nativity Pageant.

Newmarket

The Town of Newmarket usually closes Water Street and other streets near Fairy Lake Park evenings during the week of Christmas to accommodate the annual pageant.

York Region Transit usually detours bus services during the event.

(YRT has not confirmed detours. this post describes how it detoured buses during the 2007 pageant.)

From 6:30 until 9 p.m. on Sunday, Monday and Tuesday December 21, 22 and 23 and from 6:30 until 8 p.m. on Wednesday, December 24, southbound buses operate along their regular route to Main Street South and Timothy Street, then detour:

eastward along Timothy; and then
southward along Prospect Street to Water Street,
resuming their regular route southward along Prospect.

Northbound buses reverse this route.

(YRT has not confirmed detours. this post describes how it detoured buses during the 2007 pageant.)

From 6:30 until 9 p.m. on December 21, 22 and 23 and from 6:30 until 8 p.m. on December 24, westbound buses operate along their regular route to Gorham and Prospect Streets, then detour:

northward along Prospect;
westward along Timothy Street; and then
southward along Main Street South to Water Street,
resuming their regular route westward along Water.

Eastbound buses reverse this routing.

Toronto

The City of Toronto will close

• Bay Street between Dundas and Queen Streets West

on Saturday evening to accommodate the fireworks display at Nathan Phillips Square.

The TTC will likely detour buses during the event.

(The TTC has not confirmed the detour. this post describes how the TTC detoured buses during previous events that closed Bay Street.)

From 6:45 until 10 p.m. on Saturday, December 20, southbound buses operate along their regular route to Bay Street and Dundas Street West, then detour:

westward along Dundas;
southward along University Avenue; and then
eastward along Adelaide Street West to Bay,
resuming their regular route southward along Bay.

Northbound buses operate along their regular route to Bay Street and Richmond Street West, then detour:

westward along Richmond;
northward along University Avenue; and then
eastward along Dundas Street West to Bay,
resuming their regular route northward along Bay.