diff --git a/IPython/nbconvert/exporters/exporter.py b/IPython/nbconvert/exporters/exporter.py
index af9da29..abff42e 100755
--- a/IPython/nbconvert/exporters/exporter.py
+++ b/IPython/nbconvert/exporters/exporter.py
@@ -33,7 +33,7 @@ from IPython.config import Config
 from IPython.nbformat import current as nbformat
 from IPython.utils.traitlets import MetaHasTraits, DottedObjectName, Unicode, List, Dict, Any
 from IPython.utils.importstring import import_item
-from IPython.utils.text import indent
+from IPython.utils.text import indent, format_date
 from IPython.utils import py3compat
 
 from IPython.nbconvert import preprocessors as nbpreprocessors
@@ -282,7 +282,7 @@ class Exporter(LoggingConfigurable):
         resources['metadata']['name'] = notebook_name
 
         modified_date = datetime.datetime.fromtimestamp(os.path.getmtime(filename))
-        resources['metadata']['modified_date'] = modified_date.strftime("%B %d, %Y")
+        resources['metadata']['modified_date'] = format_date(modified_date)
         
         with io.open(filename) as f:
             return self.from_notebook_node(nbformat.read(f, 'json'), resources=resources,**kw)
diff --git a/IPython/nbconvert/preprocessors/sphinx.py b/IPython/nbconvert/preprocessors/sphinx.py
index 453a9c0..90cd063 100755
--- a/IPython/nbconvert/preprocessors/sphinx.py
+++ b/IPython/nbconvert/preprocessors/sphinx.py
@@ -30,6 +30,7 @@ from pygments.formatters import LatexFormatter
 # Our own imports
 # Configurable traitlets
 from IPython.utils.traitlets import Unicode, Bool
+from IPython.utils.text import format_date
 
 # Needed to override preprocessor
 from .base import (Preprocessor)
@@ -158,10 +159,7 @@ class SphinxPreprocessor(Preprocessor):
             if self.publish_date:
                 resources["sphinx"]["date"] = self.publish_date
             elif len(resources['metadata']['modified_date'].strip()) == 0:
-                if sys.platform == 'win32':
-                    resources["sphinx"]["date"] = date.today().strftime("%B %d, %Y")
-                else:
-                    resources["sphinx"]["date"] = date.today().strftime("%B %-d, %Y")
+                resources["sphinx"]["date"] = format_date(date.today())
             else:
                 resources["sphinx"]["date"] = resources['metadata']['modified_date']
             
@@ -223,10 +221,7 @@ class SphinxPreprocessor(Preprocessor):
         if resources['metadata']['modified_date']:
             default_date = resources['metadata']['modified_date']
         else:
-            if sys.platform == 'win32':
-                default_date = date.today().strftime("%B %d, %Y")
-            else:
-                default_date = date.today().strftime("%B %-d, %Y")
+            default_date = format_date(date.today())
             
         user_date = console.input("Date (deafults to \"" + default_date + "\"): ")
         if len(user_date.strip()) == 0:
diff --git a/IPython/utils/text.py b/IPython/utils/text.py
index 55b8861..1a3546a 100644
--- a/IPython/utils/text.py
+++ b/IPython/utils/text.py
@@ -21,6 +21,7 @@ Inheritance diagram:
 
 import os
 import re
+import sys
 import textwrap
 from string import Formatter
 
@@ -711,3 +712,21 @@ def columnize(items, separator='  ', displaywidth=80):
     fmatrix = [filter(None, x) for x in matrix]
     sjoin = lambda x : separator.join([ y.ljust(w, ' ') for y, w in zip(x, info['columns_width'])])
     return '\n'.join(map(sjoin, fmatrix))+'\n'
+
+
+def format_date(date):
+    """ Format a datetime object as a string.
+
+    Parameters
+    ----------
+    date : datetime object
+        Date to be formatted.
+
+    Returns
+    -------
+    The formatted date string (ie "July 1, 1990")
+    """
+    if sys.platform == 'win32':
+        return date.strftime("%B {0}, %Y").format(date.day)
+    else:
+        return date.strftime("%B %-d, %Y")
\ No newline at end of file