diff --git a/CLAUDE.md b/CLAUDE.md
index 438fb6c..7813e62 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -126,6 +126,25 @@ volume-mounted `/data` inside the container) holds the calendar pull
 schedule — this is live user data, not deploy-managed. `.env` holds
 `HA_WEBHOOK_URL` and is server-only, gitignored, never committed.
 
+**Container timezone (fixed 2026-09-08):** the container previously had no
+timezone configured — `python:3.12-slim` defaults to UTC and the
+`/etc/localtime` bind mount in `docker-compose.yml` was commented out — so
+`calendar_run_time` (and the `datetime.now()` call in `scraper.py` that
+picks which week to fetch) were evaluated against UTC, not the user's
+local clock. This happened to be masked because Arizona (no DST) and
+Pacific Daylight Time are both UTC-7 right now, but would have silently
+drifted the actual fire time by an hour once PDT becomes PST in November.
+Fixed by uncommenting the `/etc/localtime:/etc/localtime:ro` bind mount
+and installing `tzdata` in the `Dockerfile` — without `tzdata`, the
+host's `/etc/localtime` (typically a symlink into `/usr/share/zoneinfo/…`)
+would dangle inside the container since that directory wouldn't exist,
+silently falling back to UTC again. Found while investigating why the
+first automatic Sunday calendar push after the 2026-09-03 pivot appeared
+not to run — that specific miss turned out to be unrelated (the school's
+Nutrislice menu was published empty for the whole week, so `_push_calendar`
+correctly skipped every day), but this latent TZ bug surfaced during the
+investigation and was worth fixing regardless.
+
 **Migration note (2026-08-25):** this container originally used a Docker
 **named volume** (`lunch-notifier_lunch-settings`) instead of a bind mount.
 That meant Unraid's Appdata Backup plugin — which only knows about
diff --git a/Dockerfile b/Dockerfile
index efd7d0b..86797db 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -8,6 +8,13 @@ LABEL net.unraid.docker.icon="http://192.168.86.33:2323/icon.png"
 
 WORKDIR /app
 
+# tzdata provides /usr/share/zoneinfo, which the host's bind-mounted
+# /etc/localtime (docker-compose.yml) is typically a symlink into — without
+# it present in the image, the symlink dangles and the container silently
+# falls back to UTC.
+RUN apt-get update && apt-get install -y --no-install-recommends tzdata \
+    && rm -rf /var/lib/apt/lists/*
+
 COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
diff --git a/docker-compose.yml b/docker-compose.yml
index cfa485d..69f0b06 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -8,6 +8,6 @@ services:
       - "2323:2323"
     volumes:
       - ./data:/data
-      # Uncomment to share host timezone so RUN_TIME matches your local clock:
-      # - /etc/localtime:/etc/localtime:ro
+      # Shares host timezone so RUN_TIME matches your local clock:
+      - /etc/localtime:/etc/localtime:ro