Different time format in script, started in shell or in cron

I try to write a python script, which analyze user logon time with "who" command.
When i start script in bash, i get this result:
USER=mnadmin tty7 2009-04-18 11:37 (:0)
But when i start script in cron, i get result like this:
USER=mnadmin tty7 Apr 18 11:37 (:0)

I see - script have different environment in both cases, but i dont know where is time format defined...
I want to get a time format like i get it in bash.
Any ideas?

Take a look at en environment variables LANG, LC_ALL, LC_TIME

Yes! It is !
I add environment variable inside my script:
os.environ["LANG"]="en_US.UTF-8"
and now the time is in right format:
USER=mnadmin tty7 2009-04-19 12:04 (:0)

Thanks!