Incorrect timezone display in task log view

[humit0]

Apache Airflow version

3.0.2

If "Other Airflow 2 version" selected, which one?

No response

What happened?

The time field in the task logs displayed on the web interface is showing an incorrect timezone.

Although the default timezone is configured to KST (+09:00) and the web display is also set to KST, the times are being displayed in UTC. And log files are also recording in UTC.

web

log file

What you think should happen instead?

How to reproduce

Configured environment variables

export AIRFLOW_HOME=/tmp/airflow
export AIRFLOW__CORE__LOAD_EXAMPLES=False
export AIRFLOW__CORE__DEFAULT_TIMEZONE=Asia/Seoul

DAG

from airflow.models import DAG
from airflow.providers.standard.operators.bash import BashOperator

default_args = {
    "owner": "airflow",
    "depends_on_past": False,
    "start_date": "2023-01-01",
    "retries": 1,
}

with DAG(
    dag_id="test_dag",
    default_args=default_args,
    schedule="@once",
) as dag:
    BashOperator(
        task_id="test_task",
        bash_command="echo '{{ ds }}'",
    )

Operating System

MacOS

Versions of Apache Airflow Providers

apache-airflow-providers-amazon==9.8.0
apache-airflow-providers-apache-spark==5.3.0
apache-airflow-providers-celery==3.11.0
apache-airflow-providers-common-compat==1.7.0
apache-airflow-providers-common-io==1.6.0
apache-airflow-providers-common-sql==1.27.1
apache-airflow-providers-http==5.3.0
apache-airflow-providers-postgres==6.2.0
apache-airflow-providers-redis==4.1.0
apache-airflow-providers-smtp==2.1.0
apache-airflow-providers-standard==1.2.0

Deployment

Virtualenv installation

Deployment details

Running with airflow standalone command

Anything else?

No response

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[AryanK1511]

I can look into this one!

[humit0]

After removing .replace(tzinfo=None) in below code

airflow/task-sdk/src/airflow/sdk/execution_time/supervisor.py

Line 1575 in 7d00e45

event["timestamp"] = msgspec.json.decode(f'"{ts}"', type=datetime).replace(tzinfo=None)

then, task log display in correct timezone.

[AryanK1511]

After removing .replace(tzinfo=None) in below code

airflow/task-sdk/src/airflow/sdk/execution_time/supervisor.py

Line 1575 in 7d00e45

event["timestamp"] = msgspec.json.decode(f'"{ts}"', type=datetime).replace(tzinfo=None)
then, task log display in correct timezone.

I see, I'll try recreating this right now and then get back to you with further updates.

[AryanK1511]

@humit0 I have an answer for you.

In the current state there is no direct config setting through the airflow.cfg file for the UI's Timezone.

The default_ui_timezone configuration was removed in PR #49176 as part of AIP-38. The UI now uses a simpler approach:

1. The UI automatically detects and uses the system timezone from the user's browser
2. Users can manually change their timezone preference through the UI's timezone selector.
3. The selected timezone is stored in the browser's localStorage, making it a per-browser setting

So, I setup airflow using the airflow standalone command just like you did. On the bottom right corner of your screen, you will see the user settings where you have the ability to set a timezone for the UI.

Checkout my example below with a DAG that I ran some time ago.

Here, I am using the UTC time zone.

However, as soon as I switch to America/Toronto, which is my timezone, the logs and the UI change as well.

I hope this answers your question. Lemme know if we can close this issue now.

[humit0]

@AryanK1511
I set default_timezone config as "Asia/Seoul" instead of default_ui_timezone configuration.

If i don't specify default_timezone option, then it works fine.

[COKID]

@AryanK1511 I set default_timezone config as "Asia/Seoul" instead of default_ui_timezone configuration.

If i don't specify default_timezone option, then it works fine.

I have same problem when I set airflow.cfg 'default_timezone = Asia/Shanghai'
When rollback this config as default as "default_timezone = utc", all work well
I get logs using api when I set my timezone, the response contains "timestamp": "2025-07-02T06:16:24.681786+08:00”, It's weird;
When I rollback config and restart airflow, I got "timestamp": "2025-07-02T08:02:42.853339Z", That's correct

[humit0]

Hello @rawwar !
I was wondering if you could explain the reason for converting this issue into a discussion. It seems there might have been a mix-up regarding the settings. To be clear, my report was about default_timezone, not default_ui_timezone, which @AryanK1511 addressed.

[MizuyoruTW]

I’m experiencing the same issue.
I’ve set default_timezone = Asia/Taipei in my airflow.cfg, and my container is also using this timezone (/etc/localtime and /etc/timezone).

For additional context, this problem is not only about the Web UI timezone. Here’s my situation:

• I always set my Web UI to UTC+8:

• But if I change the Web UI to UTC+0:

The timestamps in the logs are always 8 hours behind compared to other places.

[labintsev]

Airflow designed for users, that may live in more than one time zone.

I always set my Web UI to UTC+8

• this is correct, UI in your local time, db logs in UTC.

But if I change the Web UI to UTC+0

• this is not correct, db logs shifted to UTC-8:00, because you set default_timezone = Asia/Taipei

https://airflow.apache.org/docs/apache-airflow/stable/authoring-and-scheduling/timezone.html