Ubuntu :: Timestamp Format - Shell Versus Cron Job

Setup: 10.04 server with "bash" as /bin/sh
When I run "ls -l" in a shell I get the following format:

Code:
-rw-r----- 1 syslog adm 0 2010-06-13 06:53 /var/log/user.log
Whereas if "ls -l" executes from a cron job the format is:

Code:
-rw-r----- 1 syslog adm 0 Jun 13 06:53 /var/log/user.log
Notice the different time format. Now I could fix this by changing the cron job to

Code:
ls -l --time-style=+%Y-%m-%d %H:%M ...
but I'm interested in knowing why this behavior occurs. What's different between the cron job and the shell?