Index: Doc/library/imaplib.rst
===================================================================
--- Doc/library/imaplib.rst	(revision 88058)
+++ Doc/library/imaplib.rst	(working copy)
@@ -85,8 +85,8 @@
 
 .. function:: Internaldate2tuple(datestr)
 
-   Converts an IMAP4 INTERNALDATE string to Coordinated Universal Time. Returns a
-   :mod:`time` module tuple.
+   Converts an IMAP4 INTERNALDATE string to local time.
+   Returns a :mod:`time` module tuple.
 
 
 .. function:: Int2AP(num)
@@ -102,7 +102,8 @@
 
 .. function:: Time2Internaldate(date_time)
 
-   Converts a :mod:`time` module tuple to an IMAP4 ``INTERNALDATE`` representation.
+   Converts a :mod:`time` module tuple (local time) to an
+   IMAP4 ``INTERNALDATE`` representation.
    Returns a string in the form: ``"DD-Mmm-YYYY HH:MM:SS +HHMM"`` (including
    double-quotes).
 
Index: Lib/imaplib.py
===================================================================
--- Lib/imaplib.py	(revision 88058)
+++ Lib/imaplib.py	(working copy)
@@ -22,7 +22,7 @@
 
 __version__ = "2.58"
 
-import binascii, errno, random, re, socket, subprocess, sys, time
+import binascii, errno, random, re, socket, subprocess, sys, time, calendar
 
 try:
     import ssl
@@ -1308,11 +1308,11 @@
 
 
 
-Mon2num = {'Jan': 1, 'Feb': 2, 'Mar': 3, 'Apr': 4, 'May': 5, 'Jun': 6,
-        'Jul': 7, 'Aug': 8, 'Sep': 9, 'Oct': 10, 'Nov': 11, 'Dec': 12}
+Mon2num = {b'Jan': 1, b'Feb': 2, b'Mar': 3, b'Apr': 4, b'May': 5, b'Jun': 6,
+        b'Jul': 7, b'Aug': 8, b'Sep': 9, b'Oct': 10, b'Nov': 11, b'Dec': 12}
 
 def Internaldate2tuple(resp):
-    """Convert IMAP4 INTERNALDATE to UT.
+    """Convert IMAP4 INTERNALDATE to local time.
 
     Returns Python time module tuple.
     """
@@ -1335,26 +1335,16 @@
     # INTERNALDATE timezone must be subtracted to get UT
 
     zone = (zoneh*60 + zonem)*60
-    if zonen == '-':
+    if zonen == b'-':
         zone = -zone
 
     tt = (year, mon, day, hour, min, sec, -1, -1, -1)
+    utc = calendar.timegm(tt) - zone
 
-    utc = time.mktime(tt)
+    return time.localtime(utc)
 
-    # Following is necessary because the time module has no 'mkgmtime'.
-    # 'mktime' assumes arg in local timezone, so adds timezone/altzone.
 
-    lt = time.localtime(utc)
-    if time.daylight and lt[-1]:
-        zone = zone + time.altzone
-    else:
-        zone = zone + time.timezone
 
-    return time.localtime(utc - zone)
-
-
-
 def Int2AP(num):
 
     """Convert integer to A-P string representation."""
@@ -1381,7 +1371,7 @@
 
 def Time2Internaldate(date_time):
 
-    """Convert 'date_time' to IMAP4 INTERNALDATE representation.
+    """Convert 'date_time' (local time) to IMAP4 INTERNALDATE representation.
 
     Return string in form: '"DD-Mmm-YYYY HH:MM:SS +HHMM"'
     """