diff --git a/include/wx/datetime.h b/include/wx/datetime.h
index 194c1f4d79..b2a33ffd9a 100644
--- a/include/wx/datetime.h
+++ b/include/wx/datetime.h
@@ -277,6 +277,15 @@ public:
         Sunday_First     // week starts with a Sunday
     };
 
+    // Currently we assume that DST is always shifted by 1 hour, this seems to
+    // be always true in practice. If this ever needs to change, search for all
+    // places using DST_OFFSET and update them.
+    enum
+    {
+        DST_OFFSET = 3600
+    };
+
+
     // helper classes
     // ------------------------------------------------------------------------
 
diff --git a/src/common/datetime.cpp b/src/common/datetime.cpp
index a1ef82772b..eddaf7977e 100644
--- a/src/common/datetime.cpp
+++ b/src/common/datetime.cpp
@@ -2066,8 +2066,7 @@ wxDateTime& wxDateTime::MakeTimezone(const TimeZone& tz, bool noDST)
     // specified.
     if ( !noDST && (IsDST() == 1) )
     {
-        // FIXME we assume that the DST is always shifted by 1 hour
-        secDiff -= 3600;
+        secDiff -= DST_OFFSET;
     }
 
     return Add(wxTimeSpan::Seconds(secDiff));
@@ -2080,8 +2079,7 @@ wxDateTime& wxDateTime::MakeFromTimezone(const TimeZone& tz, bool noDST)
     // See comment in MakeTimezone() above, the logic here is exactly the same.
     if ( !noDST && (IsDST() == 1) )
     {
-        // FIXME we assume that the DST is always shifted by 1 hour
-        secDiff -= 3600;
+        secDiff -= DST_OFFSET;
     }
 
     return Subtract(wxTimeSpan::Seconds(secDiff));
diff --git a/src/common/datetimefmt.cpp b/src/common/datetimefmt.cpp
index 8fbf1e0034..86aca9f32f 100644
--- a/src/common/datetimefmt.cpp
+++ b/src/common/datetimefmt.cpp
@@ -689,10 +689,7 @@ wxString wxDateTime::Format(const wxString& formatp, const TimeZone& tz) const
                         // time in the local time zone to the user.
                         if ( ofs == -wxGetTimeZone() && IsDST() == 1 )
                         {
-                            // FIXME: As elsewhere in wxDateTime, we assume
-                            // that the DST is always 1 hour, but this is not
-                            // true in general.
-                            ofs += 3600;
+                            ofs += DST_OFFSET;
                         }
 
                         if ( ofs < 0 )