PHP Warning: strtotime(): It is not safe to rely on the system's timezone settings.

有三种解决办法：

1. php文件中设置时区

    <?php

         date_default_timezone_set(‘Asia/Shanghai‘);

         echo strtotime(‘2012-9-3‘);

    ?>

2. 设置php.ini

   data.timezone = "Asia/Shanghai"

3. 设置date_timezone.ini

  date.timezone = "Asia/Shanghai"

如果使用zend server ，在 Server Setup －> Directives -> date.timezone 设置成Asia/Shanghai 。
然后点击Save Changes, Restart PHP

对应的时区参考：timezones

PHP Warning: strtotime(): It is not safe to rely on the system's timezone settings.

原文：http://www.cnblogs.com/baocheng/p/3944397.html