diff --git a/src/basic/time-util.c b/src/basic/time-util.c
index 8e0d4cc030..40d1bf1e09 100644
--- a/src/basic/time-util.c
+++ b/src/basic/time-util.c
@@ -889,7 +889,11 @@ static int parse_timestamp_impl(
                 if (!k || *k != ' ')
                         continue;
 
+#ifdef __GLIBC__
+                /* musl does not set tm_wday field and set 0 unless it is explicitly requested by %w or so.
+                 * In the below, let's only check tm_wday field only when built with glibc. */
                 weekday = day->nr;
+#endif
                 t = k + 1;
                 break;
         }