diff --git a/dlls/comctl32/datetime.c b/dlls/comctl32/datetime.c
index 2904d41f5f1..f53045e2b9c 100644
--- a/dlls/comctl32/datetime.c
+++ b/dlls/comctl32/datetime.c
@@ -26,8 +26,8 @@ static BOOL
 
 DATETIME_SendSimpleNotify (HWND hwnd, UINT code);
 
-extern char *days[];  /* from ole/parsedt.c */
-
+static const char * const days[] = {"Sunday", "Monday", "Tuesday", "Wednesday",
+"Thursday", "Friday", "Saturday", NULL};
 
 static LRESULT
 DATETIME_GetSystemTime (HWND hwnd, WPARAM wParam, LPARAM lParam )
diff --git a/dlls/comctl32/monthcal.c b/dlls/comctl32/monthcal.c
index 07cd7392077..2861f71b231 100644
--- a/dlls/comctl32/monthcal.c
+++ b/dlls/comctl32/monthcal.c
@@ -34,13 +34,13 @@ DEFAULT_DEBUG_CHANNEL(monthcal)
  * we want full month-names, and abbreviated weekdays, so these are
  * defined here */
 
-extern int mdays[];    
+static const int mdays[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 0};
 
-char *monthtxt[] = {"January", "February", "March", "April", "May", 
+const char * const monthtxt[] = {"January", "February", "March", "April", "May", 
                       "June", "July", "August", "September", "October", 
                       "November", "December"};
-char *daytxt[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
-int DayOfWeekTable[] = {0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4};
+const char * const daytxt[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
+static const int DayOfWeekTable[] = {0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4};
 
 
 #define MONTHCAL_GetInfoPtr(hwnd) ((MONTHCAL_INFO *)GetWindowLongA(hwnd, 0))
@@ -337,7 +337,8 @@ static void MONTHCAL_Refresh(HWND hwnd, HDC hdc)
   HBRUSH hbr;
   HFONT currentFont;
   /* LOGFONTA logFont; */
-  char buf[20], *thisMonthtxt;
+  char buf[20];
+  const char *thisMonthtxt;
   COLORREF oldTextColor, oldBkColor;
   DWORD dwStyle = GetWindowLongA(hwnd, GWL_STYLE);
   BOOL prssed;
diff --git a/dlls/oleaut32/parsedt.c b/dlls/oleaut32/parsedt.c
index 82476adc943..8b9697a8711 100644
--- a/dlls/oleaut32/parsedt.c
+++ b/dlls/oleaut32/parsedt.c
@@ -58,12 +58,12 @@ static int	DecodeTimezone(char *str, int *tzp);
 #define USE_DATE_CACHE 1
 #define ROUND_ALL 0
 
-int			mdays[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 0};
+static const int mdays[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 0};
 
-char	   *months[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
+static const char * const months[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", NULL};
 
-char	   *days[] = {"Sunday", "Monday", "Tuesday", "Wednesday",
+static const char * const days[] = {"Sunday", "Monday", "Tuesday", "Wednesday",
 "Thursday", "Friday", "Saturday", NULL};
 
 /* those three vars are useless, and not even initialized, so 
diff --git a/include/monthcal.h b/include/monthcal.h
index 23dbcbfa0a2..794f4cf871b 100644
--- a/include/monthcal.h
+++ b/include/monthcal.h
@@ -76,8 +76,8 @@ typedef struct tagMONTHCAL_INFO
 
 extern void MONTHCAL_CopyTime (const SYSTEMTIME *from, SYSTEMTIME *to);
 extern int MONTHCAL_CalculateDayOfWeek (DWORD day, DWORD month, DWORD year);
-extern char *daytxt[];
-extern char *monthtxt[];
+extern const char * const daytxt[];
+extern const char * const monthtxt[];
 extern void MONTHCAL_Register (void);
 extern void MONTHCAL_Unregister (void);