DeprecationWarning: Parsing dates involving a day of month without a year specified is ambiguious

[Zian]

Python 3.13.7 displays the following message after line 8 of the below script that uses the progressbar module.

DeprecationWarning: Parsing dates involving a day of month without a year specified is ambiguious and fails to parse leap day. The default behavior will change in Python 3.15 to either always raise an exception or to use a different default year (TBD).
To avoid trouble, add a specific year to the input & format.
See python/cpython#70647.

Script

import time
import progressbar

SLEEP_DURATION_IN_SECONDS = 3

example_list = [1, 2, 3]
completed_items = 0
with progressbar.ProgressBar(max_value=len(example_list)) as prg:
	time.sleep(SLEEP_DURATION_IN_SECONDS)
	completed_items = completed_items + 1
	prg.update(completed_items)

Steps to Reproduce the Bug

1. Install Python 3.13.7.
2. Install the progressbar module
3. Run the aforementioned script.

Environmental Details

• Microsoft Windows Version 22H2 (OS Build 19045.6937)
• Python 3.13.7 ("Python 3.13.7 | packaged by Anaconda, Inc. | (main, Sep 11 2025, 16:13:29) [MSC v.1938 64 bit (AMD64)] on win32")
• progressbar2 Version 4.5.0