diff --git a/sphinx/util/i18n.py b/sphinx/util/i18n.py
index 14b190406..d0b2fa1e2 100644
--- a/sphinx/util/i18n.py
+++ b/sphinx/util/i18n.py
@@ -274,7 +274,7 @@ def format_date(format: str, date: datetime = None, language: str = None) -> str
         if source_date_epoch is not None:
             date = datetime.utcfromtimestamp(float(source_date_epoch))
         else:
-            date = datetime.now()
+            date = datetime.utcnow()
 
     result = []
     tokens = date_format_re.split(format)