diff --git a/src/corelib/tools/qdatetime.cpp b/src/corelib/tools/qdatetime.cpp
index 491ed993018..29c8dbb2ea5 100644
--- a/src/corelib/tools/qdatetime.cpp
+++ b/src/corelib/tools/qdatetime.cpp
@@ -2159,7 +2159,7 @@ static int qt_timezone()
         //   number of seconds west of UTC.
         // - It also takes DST into account, so we need to adjust it to always
         //   get the Standard Time offset.
-        return -t.tm_gmtoff + (t.tm_isdst ? SECS_PER_HOUR : 0L);
+        return -t.tm_gmtoff + (t.tm_isdst ? (long)SECS_PER_HOUR : 0L);
 #else
         return timezone;
 #endif // Q_OS_WIN