diff --git a/libc/time/lib_daysbeforemonth.c b/libc/time/lib_daysbeforemonth.c
index 8c66dc808b..8c09c2203e 100644
--- a/libc/time/lib_daysbeforemonth.c
+++ b/libc/time/lib_daysbeforemonth.c
@@ -91,8 +91,8 @@ static const uint16_t g_daysbeforemonth[13] =
 
 int clock_daysbeforemonth(int month, bool leapyear)
 {
-  int retval = g_daysbeforemonth[month-1];
-  if (month > 2 && leapyear)
+  int retval = g_daysbeforemonth[month];
+  if (month >= 2 && leapyear)
     {
       retval++;
     }