import netCDF4
root = 'http://dm2.caricoos.org/thredds/dodsC/roms/20131203/ocean_his_%4.4d.nc'
files = [root % d for d in range(1,3)]
nc = netCDF4.MFDataset(files)
def start_stop(nc,tvar):
ncv = nc.variables
time_var = ncv[tvar]
first = netCDF4.num2date(time_var[0],time_var.units)
last = netCDF4.num2date(time_var[-1],time_var.units)
print first.strftime('%Y-%b-%d %H:%M')
print last.strftime('%Y-%b-%d %H:%M')
tvar = 'ocean_time'
start_stop(nc,tvar)
1968-May-23 00:00 1968-May-23 01:00