Selecting unique rows based on the maximum date
CREATE OR REPLACE VIEW schema.view AS 
SELECT DISTINCT ON (thing_id, forecast_datetime)
       forecast_datetime,
       interval,
       time_zone,
       file_date,
       thing_id, 
       thing_name,
       other_cols...
FROM   schema.orig_table
ORDER  BY  thing_id, forecast_datetime ASC, file_date DESC 


This appears to have worked perfectly.