C:\cygwin\usr\share\doc\Cygwin\cron.README

Command line option `-D' added to allow cron to run under
cygrunsrv. Install as service like that:

	cygrunsrv -I cron -p /usr/sbin/cron -a -D

`root' with uid 0 is substituted by `SYSTEM' with uid 18.

$PATH is never destroyed unless a PATH is explicitely given in the
crontab file. In that case you are on your own. Never forget to
add the Windows system directories to $PATH then!

Mail is send using /usr/sbin/ssmtp instead of using sendmail.

The cron dir is "/var/cron".

By default everyone may use crontab. To change that, add an
appropriate allow or deny file (or both). See `man 1 crontab'.

The installation routine installs more stuff.