diff -r cdfeb0811a87 sys/src/libc/port/date.c
--- a/sys/src/libc/port/date.c	Tue Sep 22 11:42:15 2020 -0700
+++ b/sys/src/libc/port/date.c	Tue Sep 22 15:17:26 2020 -0700
@@ -330,7 +330,7 @@
 	if(d < 0)
 		d += mdays[m - 1];
 
-	tm->yday = d;
+	tm->yday = d - 1;
 	for(i = 0; i < m - 1; i++)
 		tm->yday += mdays[i];
 	if(m > 1 && isleap(y))