CDO

Hello,

I am working with a monthly dataset from AIRS. I am outputting monthly averaged precipitable vapor data for each month between Sep 2002 and Dec 2010. The units for precipitable vapor are given in kg/m^2, which is equivalent to millimeters. I want to change the units to mm/day, but I want to account for the number of days per month (I could divide the monthly value by 30 but this isn't completely accurate). Is there a cdo command that takes care of this?

Thanks,

-Justin