iCal with week numbers1 minute to read
The new iCal for Mountain Lion has the ability to add the week numbers information to your weeks. This is really well made, since you can see it on the small current month calendar, your day, week, month and year view!
To enable it, just go to the
iCal Preferences -> Advanced and tick the box "Show week numbers", and there you go.
If you need this information on older versions of OS X, please google it. You can subscribe to an external iCal that provides that information, but don't expect it to be so neat. :)