diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 955397ee9dc..61ec049f054 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -2776,9 +2776,18 @@ exec_command_watch(PsqlScanState scan_state, bool active_branch,
 		/* Convert optional sleep-length argument */
 		if (opt)
 		{
-			sleep = strtod(opt, NULL);
-			if (sleep <= 0)
-				sleep = 1;
+			char	   *opt_end;
+
+			errno = 0;
+			sleep = strtod(opt, &opt_end);
+			if (sleep < 0 || *opt_end || errno == ERANGE)
+			{
+				pg_log_error("\\watch: incorrect interval value '%s'", opt);
+				free(opt);
+				resetPQExpBuffer(query_buf);
+				psql_scan_reset(scan_state);
+				return PSQL_CMD_ERROR;
+			}
 			free(opt);
 		}
 
@@ -5183,6 +5192,9 @@ do_watch(PQExpBuffer query_buf, double sleep)
 		if (pagerpipe && ferror(pagerpipe))
 			break;
 
+		if (sleep == 0)
+			continue;
+
 #ifdef WIN32
 
 		/*
diff --git a/src/bin/psql/t/001_basic.pl b/src/bin/psql/t/001_basic.pl
index 0f394420b26..64ce0120621 100644
--- a/src/bin/psql/t/001_basic.pl
+++ b/src/bin/psql/t/001_basic.pl
@@ -350,4 +350,21 @@ psql_like(
 	'\copy from with DEFAULT'
 );
 
+# Check \watch errors
+psql_fails_like(
+	$node,
+	'SELECT 1;\watch -10',
+	qr/incorrect interval value '-10'/,
+	'\watch, negative interval');
+psql_fails_like(
+	$node,
+	'SELECT 1;\watch 10ab',
+	qr/incorrect interval value '10ab'/,
+	'\watch incorrect interval');
+psql_fails_like(
+	$node,
+	'SELECT 1;\watch 10e400',
+	qr/incorrect interval value '10e400'/,
+	'\watch out-of-range interval');
+
 done_testing();