mask nc using shapefile and calculate average and anomaly

[shuai-zhou]

Dear all,

New user to xarray here. This is a cross-posting that can also be found here.

Suppose I have the monthly temperature data download temperature file and the state-level US shapefile download shapefile here. How can I get the county-level average temperature for each state like the following table (of course, no need to sort state by name):

state	avg_temp
AL	xx
AR	xx
...	...
WY	xx

Also, how can I get the temperature anomaly of the year 2019 relative to baseline years from 2000 to 2010 for each state (like the data format above)? I have been trying with rioxarray, regionmask, and function proposed by @shoyer here, but was still unclear about the workflow of these tasks. Any help would be much appreciated!

[mathause]

Thanks for your question - I think this is only marginally related to xarray so I'll answer on stackoverflow.