diff --git a/pandas/_libs/tslibs/parsing.pyx b/pandas/_libs/tslibs/parsing.pyx index ad723df485ba6..94c549cbd3db0 100644 --- a/pandas/_libs/tslibs/parsing.pyx +++ b/pandas/_libs/tslibs/parsing.pyx @@ -936,8 +936,10 @@ def guess_datetime_format(dt_str: str, bint dayfirst=False) -> str | None: datetime_attrs_to_format.remove(day_attribute_and_format) datetime_attrs_to_format.insert(0, day_attribute_and_format) - # same default used by dateutil - default = datetime.now().replace(hour=0, minute=0, second=0, microsecond=0) + # Use this instead of the dateutil default of + # `datetime.now().replace(hour=0, minute=0, second=0, microsecond=0)` + # as that causes issues on the 29th of February. + default = datetime(1970, 1, 1) try: parsed_datetime = dateutil_parse( dt_str,