diff --git a/django/utils/dateformat.py b/django/utils/dateformat.py
index 0e6541c721..9a296c3f2d 100644
--- a/django/utils/dateformat.py
+++ b/django/utils/dateformat.py
@@ -166,8 +166,8 @@ class DateFormat(TimeFormat):
 
     def O(self):
         "Difference to Greenwich time in hours; e.g. '+0200'"
-        tz = self.timezone.utcoffset(self.data)
-        return u"%+03d%02d" % (tz.seconds // 3600, (tz.seconds // 60) % 60)
+        seconds = self.Z()
+        return u"%+03d%02d" % (seconds // 3600, (seconds // 60) % 60)
 
     def r(self):
         "RFC 822 formatted date; e.g. 'Thu, 21 Dec 2000 16:01:07 +0200'"