diff --git a/include/posix/time.h b/include/posix/time.h
index 285d4ae44d0..ce0648ed68e 100644
--- a/include/posix/time.h
+++ b/include/posix/time.h
@@ -56,11 +56,11 @@ extern "C" {
 #endif
 
 #ifndef CLOCK_REALTIME
-#define CLOCK_REALTIME 0
+#define CLOCK_REALTIME 1
 #endif
 
 #ifndef CLOCK_MONOTONIC
-#define CLOCK_MONOTONIC 1
+#define CLOCK_MONOTONIC 4
 #endif
 
 #define NSEC_PER_MSEC (NSEC_PER_USEC * USEC_PER_MSEC)