diff --git a/library/src/main/java/com/codetroopers/betterpickers/recurrencepicker/EventRecurrenceFormatter.java b/library/src/main/java/com/codetroopers/betterpickers/recurrencepicker/EventRecurrenceFormatter.java
index 3e08d041..a2fbba8f 100644
--- a/library/src/main/java/com/codetroopers/betterpickers/recurrencepicker/EventRecurrenceFormatter.java
+++ b/library/src/main/java/com/codetroopers/betterpickers/recurrencepicker/EventRecurrenceFormatter.java
@@ -110,7 +110,9 @@ public static String getRepeatString(Context context, Resources r, EventRecurren
                     if(dayNumber == RecurrencePickerDialogFragment.LAST_NTH_DAY_OF_WEEK){
                         dayNumber = 5;
                     }
-                    details = mMonthRepeatByDayOfWeekStrs[weekday][dayNumber - 1];
+                    if (dayNumber > 0) {
+                        details = mMonthRepeatByDayOfWeekStrs[weekday][dayNumber - 1];
+                    }
                 }
                 return r.getQuantityString(R.plurals.monthly, interval, interval, details) + endString;
             }