So I've been thinking about this and the timeline doesn't seem to be 100% accurate. I also checked the corresponding page on the wiki and it makes even less sense. Here's what I mean:
The events of season 1 seem to occur over a 3.5-month span:
- From the tapes in Crawford we can conclude that the apocalypse started sometime in July.
- There's a 3-month gap between A New Day and Starved For Help
- About 1-week gap between Starved For Help and Long Road Ahead
- A few days to a week from the beginning of Long Road Ahead till the end of No Time Left
Which means season 1 started ~mid July and ended ~early November
Christa seemed to be aware of her pregnancy in Season 1 and she even showed symptoms like nausea, although she had no visible bump, so I think it's safe to assume she was around her 2nd month. Early in All That Remains she seemed to be late in her pregnancy, possibly in the 8th or 9th month. Assuming the gap between the ending of Season 1 and the beginning of All That Remains is about 6-7 months, the restroom scene and Omid's death happened in May or June of the following year.
Then we have another 16-month gap, plus a week during which the events of All That Remains and A House Divided occured, which means the latter takes place sometime in October at the latest.
Yet there's a Christmas tree and a chapter named Christmas Dinner, implying the episode takes place in December.
So either Kenny's group is celebrating Christmas 2 months early or Telltale should've added 2 more months in that 16-month gap.