html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/1480#issuecomment-316810057,https://api.github.com/repos/pydata/xarray/issues/1480,316810057,MDEyOklzc3VlQ29tbWVudDMxNjgxMDA1Nw==,1197350,2017-07-20T19:46:15Z,2017-07-20T19:46:15Z,MEMBER,"> As I understand he is getting monthly data out of groupby-method and in his example the ""time"" survives. It seems to be that the functionality of groupby-month changed during the years, because the groupby-method in Nicolas's example did not aggregate same calendar month to one time stamp.

There has been no change in xarray's groupby behavior. Nicolas' example would work with today's code. When you call `datset.groupby('time.month').mean('time')`, you remove the time dimension by aggregating over it. If you had applied a different (non-reducing) function to the group (e.g. `datset.groupby('time.month').apply(lambda x : x**2)`, you would preserve the time dimension.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,243270042