t.rast.list input=precipitation_1950_2013_monthly_mm \
       where="start_time = datetime(start_time, 'start of year', '0 month')"
 precipitation_monthly_mm_0 soeren 1950-01-01 00:00:00 1950-02-01 00:00:00
 precipitation_monthly_mm_12 soeren 1951-01-01 00:00:00 1951-02-01 00:00:00
 ...
 precipitation_monthly_mm_732 soeren 2011-01-01 00:00:00 2011-02-01 00:00:00
 precipitation_monthly_mm_744 soeren 2012-01-01 00:00:00 2012-02-01 00:00:00
 precipitation_monthly_mm_756 soeren 2013-01-01 00:00:00 2013-02-01 00:00:00