WORLDCLIM 

Q: The data seem awkward (the numbers are very large) 

A1: Note that temperature is expressed as degree C * 10

A2: You have used ArcView to import generic grid files. That creates a problem as ArcView assumes that BIL files do not have negative values. These values (x) are replaced by (65535 - x); E.g., -10 becomes 65525. The nodata value of -9999 is not recognized... Same can happen with ArcInfo, unless you use the import script.