Resample time series in pandas to a weekly interval

You will be much safer with resampling based on days and then slicing every 7th day, e.g:

ts.resample('D').interpolate()[::7]

See the underlying problem with other approaches in this open pandas issue on github:

https://github.com/pandas-dev/pandas/issues/16381

You can pass anchored offsets to resample, among other options they cover this case.

For example the weekly frequency from Monday:

ts.resample('W-MON')

Neither Andy Haydens nor denfromufas answer worked for me but that did:

df.resample('W', label='left', loffset=pd.DateOffset(days=1))

as described in that answer: https://stackoverflow.com/a/46712821/1743551