Does Heroku support a per‑dyno time zone setting for platform‑generated logs and scheduler events?

Direct answer

No. Heroku does not provide a per-dyno time zone setting for platform-generated logs, metrics, or Scheduler events. Those timestamps are emitted in UTC, and no documented feature rewrites them based on a dyno-level TZ value.

Confirmed behavior vs. likely explanation

Confirmed: Dyno containers run with the system clock in UTC. Config vars are application-wide, not scoped to individual dynos. Logplex, router logs, and platform metrics are produced outside your application process and are timestamped in UTC.

Likely explanation: A TZ config var is an ordinary environment variable. It can affect your own process if the runtime and installed tzdata honor it, but it does not reach platform components. Heroku Scheduler runs one-off dynos under the app config; a schedule time-zone selection, if available, controls when a job fires, not the time zone of the platform log or metric timestamps it produces.

What to do instead

1. Keep platform-generated timestamps in UTC.
2. Convert to a regional zone at the consumer: use a log drain or log-management viewer that renders local time.
3. For Scheduler runs, convert the run time to regional display only in your reporting or UI code.
4. If your application must emit regional timestamps, include an explicit offset in the log line, or store UTC plus a separate zone identifier. Do not rely on the platform to infer the zone.

Verification

Confirm the dyno clock remains UTC and that TZ changes only the app environment:

heroku run date -u
heroku run bash -c 'echo "$TZ"; date'

After setting TZ, trigger a Scheduler job and inspect heroku logs or a drain. Platform timestamps should remain UTC. Because platform behavior can change, verify against the current Heroku Scheduler and Logplex documentation before relying on any time-zone assumption.