diff --git a/lib/google/Google_Client.php b/lib/google/Google_Client.php
index e6026a1a3b6..3e12137a8da 100644
--- a/lib/google/Google_Client.php
+++ b/lib/google/Google_Client.php
@@ -30,7 +30,8 @@ if (! function_exists('http_build_query')) {
 }
 
 if (! ini_get('date.timezone') && function_exists('date_default_timezone_set')) {
-  date_default_timezone_set('UTC');
+  // Library hack. See MDL-42808.
+  // date_default_timezone_set('UTC');
 }
 
 // hack around with the include paths a bit so the library 'just works'
diff --git a/lib/google/readme_moodle.txt b/lib/google/readme_moodle.txt
index 946aa226b56..8bb8410de4a 100644
--- a/lib/google/readme_moodle.txt
+++ b/lib/google/readme_moodle.txt
@@ -10,6 +10,12 @@ that was that we could force Google lib to use our implementation of curl.
 If you upgrade the library, please check if the method Google_CurlIO::makeRequest()
 has been updated and would require change in moodle_google_curlio.
 
+Library hack
+------------
+
+* The file Google_Client.php resets the timezone to UTC. The line
+  date_default_timezone_set('UTC'); should be commented out. See MDL-42808.
+
 Information
 -----------