From 7bdb6d8498226bc4c55ddde8a6d5ee654c10413f Mon Sep 17 00:00:00 2001
From: Marco Gorelli <33491632+MarcoGorelli@users.noreply.github.com>
Date: Thu, 29 Feb 2024 09:05:04 +0000
Subject: [PATCH 1/2] try fix ci

---
 pandas/_libs/tslibs/parsing.pyx | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/pandas/_libs/tslibs/parsing.pyx b/pandas/_libs/tslibs/parsing.pyx
index ad723df485ba6..f144e88a7b27c 100644
--- a/pandas/_libs/tslibs/parsing.pyx
+++ b/pandas/_libs/tslibs/parsing.pyx
@@ -936,8 +936,7 @@ 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)
+    default = datetime(1970, 1, 1)
     try:
         parsed_datetime = dateutil_parse(
             dt_str,

From d7eab7c9ac03d232c1ffeacc57240d4b81f17fb3 Mon Sep 17 00:00:00 2001
From: Marco Gorelli <33491632+MarcoGorelli@users.noreply.github.com>
Date: Thu, 29 Feb 2024 17:18:21 +0000
Subject: [PATCH 2/2] add comment

---
 pandas/_libs/tslibs/parsing.pyx | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pandas/_libs/tslibs/parsing.pyx b/pandas/_libs/tslibs/parsing.pyx
index f144e88a7b27c..94c549cbd3db0 100644
--- a/pandas/_libs/tslibs/parsing.pyx
+++ b/pandas/_libs/tslibs/parsing.pyx
@@ -936,6 +936,9 @@ 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)
 
+    # 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(