diff --git a/doc/api/os.md b/doc/api/os.md
index fec69aaf47527a..01496812d7f488 100644
--- a/doc/api/os.md
+++ b/doc/api/os.md
@@ -416,6 +416,19 @@ changes:
 Returns the operating system's default directory for temporary files as a
 string.
 
+On Windows, the result can be overridden by `TEMP` and `TMP` environment variables, and
+`TEMP` takes precedence over `TMP`. If neither is set, it defaults to `%SystemRoot%\temp`
+or `%windir%\temp`.
+
+On non-Windows platforms, `TMPDIR`, `TMP` and `TEMP` environment variables will be checked
+to override the result of this method, in the described order. If none of them is set, it
+defaults to `/tmp`.
+
+Some operating system distributions would either configure `TMPDIR` (non-Windows) or
+`TEMP` and `TMP` (Windows) by default without additional configurations by the system
+administrators. The result of `os.tmpdir()` typically reflects the system preference
+unless it's explicitly overridden by the users.
+
 ## `os.totalmem()`
 
 <!-- YAML