diff -r ac176a69d188 Lib/_strptime.py
--- a/Lib/_strptime.py	Sun Dec 28 22:14:23 2014 -0600
+++ b/Lib/_strptime.py	Wed Dec 31 19:26:40 2014 +0200
@@ -18,7 +18,8 @@ from re import IGNORECASE
 from re import escape as re_escape
 from datetime import (date as datetime_date,
                       timedelta as datetime_timedelta,
-                      timezone as datetime_timezone)
+                      timezone as datetime_timezone,
+                      _is_leap)
 try:
     from _thread import allocate_lock as _thread_allocate_lock
 except ImportError:
@@ -348,9 +349,9 @@ def _strptime(data_string, format="%a %b
     # though
     week_of_year = -1
     week_of_year_start = -1
-    # weekday and julian defaulted to -1 so as to signal need to calculate
+    # weekday and julian defaulted to None so as to signal need to calculate
     # values
-    weekday = julian = -1
+    weekday = julian = None
     found_dict = found.groupdict()
     for group_key in found_dict.keys():
         # Directives not explicitly handled below:
@@ -452,14 +453,18 @@ def _strptime(data_string, format="%a %b
         year = 1900
     # If we know the week of the year and what day of that week, we can figure
     # out the Julian day of the year.
-    if julian == -1 and week_of_year != -1 and weekday != -1:
+    if julian is None and week_of_year != -1 and weekday is not None:
         week_starts_Mon = True if week_of_year_start == 0 else False
         julian = _calc_julian_from_U_or_W(year, week_of_year, weekday,
                                             week_starts_Mon)
+        if julian <= 0:
+            raise ValueError('weekday before the start of the year')
+        if julian > 365 + _is_leap(year):
+            raise ValueError('weekday after the end of the year')
     # Cannot pre-calculate datetime_date() since can change in Julian
     # calculation and thus could have different value for the day of the week
     # calculation.
-    if julian == -1:
+    if julian is None:
         # Need to add 1 to result since first day of the year is 1, not 0.
         julian = datetime_date(year, month, day).toordinal() - \
                   datetime_date(year, 1, 1).toordinal() + 1
@@ -469,7 +474,7 @@ def _strptime(data_string, format="%a %b
         year = datetime_result.year
         month = datetime_result.month
         day = datetime_result.day
-    if weekday == -1:
+    if weekday is None:
         weekday = datetime_date(year, month, day).weekday()
     # Add timezone info
     tzname = found_dict.get("Z")
diff -r ac176a69d188 Lib/datetime.py
--- a/Lib/datetime.py	Sun Dec 28 22:14:23 2014 -0600
+++ b/Lib/datetime.py	Wed Dec 31 19:26:40 2014 +0200
@@ -2143,7 +2143,7 @@ else:
          _check_date_fields, _check_int_field, _check_time_fields,
          _check_tzinfo_arg, _check_tzname, _check_utc_offset, _cmp, _cmperror,
          _date_class, _days_before_month, _days_before_year, _days_in_month,
-         _format_time, _is_leap, _isoweek1monday, _math, _ord2ymd,
+         _format_time, _isoweek1monday, _math, _ord2ymd,
          _time, _time_class, _tzinfo_class, _wrap_strftime, _ymd2ord)
     # XXX Since import * above excludes names that start with _,
     # docstring does not get overwritten. In the future, it may be
diff -r ac176a69d188 Lib/test/test_strptime.py
--- a/Lib/test/test_strptime.py	Sun Dec 28 22:14:23 2014 -0600
+++ b/Lib/test/test_strptime.py	Wed Dec 31 19:26:40 2014 +0200
@@ -494,6 +494,33 @@ class CalculationTests(unittest.TestCase
         test_helper((2006, 12, 31), "Last Sunday of 2006")
         test_helper((2006, 12, 24), "Second to last Sunday of 2006")
 
+    def test_ranges(self):
+        def check(value, format, result):
+            self.assertEqual(_strptime._strptime_time(value, format)[:], result)
+        def check_invalid(value, format):
+            with self.assertRaises(ValueError):
+                _strptime._strptime_time(value, format)
+
+        check('2015 1 6', '%Y %W %w', (2015, 1, 10, 0, 0, 0, 5, 10, -1))
+        check_invalid('2015 1 7', '%Y %W %w')
+        check('2015 0 4', '%Y %U %w', (2015, 1, 1, 0, 0, 0, 3, 1, -1))
+        check('2015 0 4', '%Y %W %w', (2015, 1, 1, 0, 0, 0, 3, 1, -1))
+        check('2015 52 4', '%Y %U %w', (2015, 12, 31, 0, 0, 0, 3, 365, -1))
+        check('2015 52 4', '%Y %W %w', (2015, 12, 31, 0, 0, 0, 3, 365, -1))
+        check_invalid('2015 0 2', '%Y %U %w')
+        check_invalid('2015 0 2', '%Y %W %w')
+        check_invalid('2015 52 5', '%Y %U %w')
+        check_invalid('2015 52 5', '%Y %W %w')
+        check('2016 0 5', '%Y %U %w', (2016, 1, 1, 0, 0, 0, 4, 1, -1))
+        check('2016 0 5', '%Y %W %w', (2016, 1, 1, 0, 0, 0, 4, 1, -1))
+        check('2016 52 6', '%Y %U %w', (2016, 12, 31, 0, 0, 0, 5, 366, -1))
+        check('2016 52 6', '%Y %W %w', (2016, 12, 31, 0, 0, 0, 5, 366, -1))
+        check_invalid('2016 0 4', '%Y %U %w')
+        check_invalid('2016 0 4', '%Y %W %w')
+        check_invalid('2016 53 0', '%Y %U %w')
+        check_invalid('2016 53 0', '%Y %W %w')
+        check_invalid('2016 54 0', '%Y %W %w')
+
 
 class CacheTests(unittest.TestCase):
     """Test that caching works properly."""