#tg reference

September:

Kaneki's date with Rize is never given a calendar date in the manga, nor the exact amount of days between him scoring a date with Rize and going on the date itself, but between Rize's Takada Building kill being found on Sept 28th, and Kaneki's "weeks" spent in the hospital before his discharge on Oct 21, we can estimate their meeting and date sometime after Sept 28th through the first week-ish of October

October:

Based on the dates of Hide's texts to Kaneki in Chapter 2 (Oct 21) and Chapter 6 (Oct 31) we know that 10 days has passed in that time.

(But personally I find it unclear which manga scenes specifically fall on what days. Technically all that's important to know is that Kaneki's been starving on his own for 10 days, in addition to "weeks" in the hospital.)

November:

The Nishiki vs Kaneki fight doesn't have a canon date but based on the other dates we have, it must happen sometime between Oct 1 - Oct 4

Touka takes Kaneki to meet Uta on a Saturday (Ch 11)

As seen on Hinami's wanted poster in Ch 20, Ryoko died around 7:30pm on Nov 9

As stated in Ch 22, Kusaba was killed at 10:30pm on the 10th of the month.

Chapter 30 states that it's been about 10 days since Kusaba's death, which brings us to Nov 20, but given that its a school day I added 1 more day to make it Monday not Sunday.

In Chapter 33 Tsukiyama invites Kaneki on a "date" in 3 days' time on Sunday

I'm not entirely sure when Kimi's kidnapping and the resulting church fight happens. I think Kaneki says he's been staying days (plural?) in Anteiku after the restaurant ordeal, but visually it looks like its only been a single day? So its possible that might be pushed a few days further

December:

Kaneki's escape from Yamori is confirmed to be at 12am on Dec 20 (which is also his birthday). The other dates you can find by working backwards from this.

Yoshimura stated the CCG would need 18-20 days to prepare to raid Aogiri (Ch 66)

Banjou's escape plan needed to wait 5 days for the safest day, as of Kaneki joining them (Ch 55)

Kaneki was kidnapped in Ch 52, Ch 53 shows a full day has passed, up to 23:33 aka 11:33pm, which then transitions to Kaneki waking in ch 54 and being brought to Tatara.