Dask is a Python-based "flexible parallel computing library for analytic computing." Dask provides a simple interface to parallel data analysis tasks without requiring parallel computing knowledge from the user. Xarray is a Python package that provides an in-memory data model (and operations on that data) consistent with the Common Data Model used by NetCDF. Together, Dask and Xarray provide a parallel-computing platform ideal for analysis of Earth System Science data. Users interact with Xarray data objects without needing to think about the parallel operations being performed by Dask "under the hood." In essence, Dask and Xarray provide a platform that can scale a user's analysis from their laptop to a high-performance computing (HPC) center or the cloud, without needing to change a single line of code!