[2026-04-02] `datetime.date.today()` local timezone

README.md

Showing how datetime.date.today() in Python is sensitive to local timezone:

$ uv run how_today.py; echo '=='; date
TZ=
today() -> 2026-04-02
impl -> 2026-04-02
full    -> 2026-04-02T13:17:19
==
Thu Apr  2 13:17:19 CDT 2026
$
$
$ TZ=America/New_York uv run how_today.py 
TZ=America/New_York
today() -> 2026-04-02
impl -> 2026-04-02
full    -> 2026-04-02T14:17:25
$
$
$ TZ=Etc/UTC uv run how_today.py 
TZ=Etc/UTC
today() -> 2026-04-02
impl -> 2026-04-02
full    -> 2026-04-02T18:17:38
$
$
$ TZ=Asia/Bangkok uv run how_today.py 
TZ=Asia/Bangkok
today() -> 2026-04-03
impl -> 2026-04-03
full    -> 2026-04-03T01:18:27

how_today.py

# Copyright (c) 2026 - Present. Workwhile, Inc. All rights reserved.
# WorkWhile Confidential - Restricted

import datetime
import os
import time


def main() -> None:
    tz = os.environ.get("TZ", "")
    print(f"TZ={tz}")  # noqa: T201

    print(f"today() -> {datetime.date.today()}")  # noqa: T201

    # FROM standard libary: lib/python3.14/_pydatetime.py
    t = time.time()
    y, m, d, hh, mm, ss, weekday, jday, dst = time.localtime(t)  # noqa: RUF059
    print(f"impl -> {y:04}-{m:02}-{d:02}")  # noqa: T201
    print(f"full    -> {y:04}-{m:02}-{d:02}T{hh:02}:{mm:02}:{ss:02}")  # noqa: T201


if __name__ == "__main__":
    main()