@fujiisoup I would like to add another example on how to update a DataArray with the interpolated data. I looked in http://xarray.pydata.org/en/stable/combining.html but couldn't work out how best to do it.

I tried using merge but it requires the DataArray's to be named.

I used concat in this example but it is not correct as I would like the coordinates to be in order (in-place may be the right word).

``` import xarray as xr import pandas as pd import numpy as np

da_dt64 = xr.DataArray([1, 3], [('time', pd.date_range('1/1/2000', '1/3/2000', periods=2))]) a = da_dt64.interp(time=np.datetime64('2000-01-02')) xr.concat([da_dt64, a], dim='time')

<xarray.DataArray (time: 3)>

array([ 1., 3., 2.])

Coordinates:

* time (time) datetime64[ns] 2000-01-01 2000-01-03 2000-01-02

```