A simple way to see what environment variables and values cron gets is to create a script like the one below and put it in crontab with a time coming soon. For instance, if it's 8:10 now:

$ cat /home/abaugher/doit
#!/bin/sh
set | sort
$ chmod 700 /home/abaugher/doit
$ crontab -l
12 8 * * * /home/abaugher/doit >/tmp/doit
[download]

At 8:12, this will run that script and save the output to /tmp/doit, which you can then view to see what it knows.