Using accurate baselines for system design is critical to begin a system design, below is a spreadsheet with the ASHRAE data pulled from the 2005 handbook.
Example of US Dewpoint Contour Map
Example of US Dewpoint Map
Click here for US Dewponit Contour Map
Click here for US Dewpoint Map
Click here for OR and WA cities design data as recorded in ASHRAE fundamentals 2005 (excel file)