diff -r 63e2a52ef34e Lib/email/utils.py
--- a/Lib/email/utils.py    Sun Mar 11 23:39:28 2012 -0400
+++ b/Lib/email/utils.py    Tue Mar 13 00:02:04 2012 +0000
@@ -405,12 +405,12 @@
     # offset has changed since time provided in dt.  This will be
     # corrected in C implementation for platforms that support
     # tm_gmtoff.
-    if time.daylight:
-        if tm.tm_isdst:
-            offset = time.altzone
-            tzname = time.tzname[1]
-        else:
-            offset = time.timezone
-            tzname = time.tzname[0]
+    if time.daylight and tm.tm_isdst:
+        offset = time.altzone
+        tzname = time.tzname[1]
+    else:
+        offset = time.timezone
+        tzname = time.tzname[0]
+
     tz = datetime.timezone(datetime.timedelta(seconds=-offset), tzname)
     return datetime.datetime.fromtimestamp(seconds, tz)
diff -r 63e2a52ef34e Lib/test/test_email/test_utils.py
--- a/Lib/test/test_email/test_utils.py Sun Mar 11 23:39:28 2012 -0400
+++ b/Lib/test/test_email/test_utils.py Tue Mar 13 00:02:04 2012 +0000
@@ -1,5 +1,7 @@
 import datetime
 from email import utils
+import test.support
+import time
 import unittest
 
 class DateTimeTests(unittest.TestCase):
@@ -46,25 +48,70 @@
 
 class LocaltimeTests(unittest.TestCase):
 
-    def test_localtime(self):
-        # Based on Issue 9527 patch
+    def test_localtime_is_tz_aware_daylight_true(self):
+        test.support.patch(self, time, 'daylight', True)
         t = utils.localtime()
         self.assertIsNot(t.tzinfo, None)
-        t0 = datetime.datetime(1970, 1, 1, tzinfo = datetime.timezone.utc)
-        t1 = utils.localtime(t0)
-        self.assertEqual(t0, t1)
-        t2 = utils.localtime(t1.replace(tzinfo=None))
-        self.assertEqual(t1, t2)
-        # The following tests use local time that is ambiguous in the
-        # US, but should work in any location
-        t0 = datetime.datetime(2010, 11, 7, 1, 30)
-        t1 = utils.localtime(t0, isdst=0)
+
+    def test_localtime_is_tz_aware_daylight_false(self):
+        test.support.patch(self, time, 'daylight', False)
+        t = utils.localtime()
+        self.assertIsNot(t.tzinfo, None)
+
+    def test_localtime_daylight_true_dst_false(self):
+        test.support.patch(self, time, 'daylight', True)
+        t0 = datetime.datetime(2012, 3, 12, 1, 1)
+        t1 = utils.localtime(t0, isdst=-1)
         t2 = utils.localtime(t1)
         self.assertEqual(t1, t2)
+
+    def test_localtime_daylight_false_dst_false(self):
+        test.support.patch(self, time, 'daylight', False)
+        t0 = datetime.datetime(2012, 3, 12, 1, 1)
+        t1 = utils.localtime(t0, isdst=-1)
+        t2 = utils.localtime(t1)
+        self.assertEqual(t1, t2)
+
+    def test_localtime_daylight_true_dst_true(self):
+        test.support.patch(self, time, 'daylight', True)
+        t0 = datetime.datetime(2012, 3, 12, 1, 1)
         t1 = utils.localtime(t0, isdst=1)
         t2 = utils.localtime(t1)
         self.assertEqual(t1, t2)
 
+    def test_localtime_daylight_false_dst_true(self):
+        test.support.patch(self, time, 'daylight', False)
+        t0 = datetime.datetime(2012, 3, 12, 1, 1)
+        t1 = utils.localtime(t0, isdst=1)
+        t2 = utils.localtime(t1)
+        self.assertEqual(t1, t2)
+
+    def test_localtime_epoch_utc_daylight_true(self):
+        test.support.patch(self, time, 'daylight', True)
+        t0 = datetime.datetime(1970, 1, 1, tzinfo = datetime.timezone.utc)
+        t1 = utils.localtime(t0)
+        self.assertEqual(t0, t1)
+
+    def test_localtime_epoch_utc_daylight_false(self):
+        test.support.patch(self, time, 'daylight', False)
+        t0 = datetime.datetime(1970, 1, 1, tzinfo = datetime.timezone.utc)
+        t1 = utils.localtime(t0)
+        self.assertEqual(t0, t1)
+
+    def test_localtime_epoch_notz_daylight_true(self):
+        test.support.patch(self, time, 'daylight', True)
+        t0 = datetime.datetime(1970, 1, 1)
+        t1 = utils.localtime(t0)
+        t2 = utils.localtime(t0.replace(tzinfo=None))
+        self.assertEqual(t1, t2)
+
+    def test_localtime_epoch_notz_daylight_false(self):
+        test.support.patch(self, time, 'daylight', False)
+        t0 = datetime.datetime(1970, 1, 1)
+        t1 = utils.localtime(t0)
+        t2 = utils.localtime(t0.replace(tzinfo=None))
+        self.assertEqual(t1, t2)
+
 
 if __name__ == '__main__':
     unittest.main()
diff -r 63e2a52ef34e Misc/ACKS
--- a/Misc/ACKS Sun Mar 11 23:39:28 2012 -0400
+++ b/Misc/ACKS Tue Mar 13 00:02:04 2012 +0000
@@ -499,6 +499,7 @@
 Matt Joiner
 Thomas Jollans
 Nicolas Joly
+Brian K. Jones
 Evan Jones
 Jeremy Jones
 Richard Jones