1 files changed, 4 insertions, 0 deletions
diff --git a/Lib/_strptime.py b/Lib/_strptime.py
index 8da4fcd..fe94361 100644
--- a/Lib/_strptime.py
+++ b/Lib/_strptime.py
@@ -514,6 +514,10 @@ def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
                                                 week_starts_Mon)
         elif iso_year is not None and iso_week is not None:
             year, julian = _calc_julian_from_V(iso_year, iso_week, weekday + 1)
+        if julian is not None and julian <= 0:
+            year -= 1
+            yday = 366 if calendar.isleap(year) else 365
+            julian += yday
 
     if julian is None:
         # Cannot pre-calculate datetime_date() since can change in Julian