diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-helpers-date.c b/jerry-core/ecma/builtin-objects/ecma-builtin-helpers-date.c
index 280a94c4b8..fd5233b56a 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-helpers-date.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-helpers-date.c
@@ -36,12 +36,12 @@
 /**
  * Day names
  */
-const char day_names_p[7][3] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" };
+const char day_names_p[7][4] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" };
 
 /**
  * Month names
  */
-const char month_names_p[12][3] = {
+const char month_names_p[12][4] = {
   "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
 };
 
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.h b/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.h
index db90bc93a6..8810bf0c37 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.h
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.h
@@ -175,8 +175,8 @@ typedef enum
 } ecma_date_timezone_t;
 
 /* ecma-builtin-helpers-date.c */
-extern const char day_names_p[7][3];
-extern const char month_names_p[12][3];
+extern const char day_names_p[7][4];
+extern const char month_names_p[12][4];
 
 int32_t ecma_date_day_from_time (ecma_number_t time);
 int32_t ecma_date_year_from_time (ecma_number_t time);