# How to forecast hierarchical time series with external unique external regressors for each base time series?

I have hierarchical time series with 70 base time series, forming 4 level of hierarchies. I am using forecast() function in R from the package forecast.

When xreg and newxreg are passed, the same covariates are applied to every series in the hierarchy.
• Create your own forecasts using any method you like, then use combinef() to reconcile them. – Rob Hyndman Apr 12 '18 at 21:29