| Ratings 
 
 
  | Year | Rank | Edo | Dev. | Games |  
  | 1930 | 870 | 2132 | (60) | 17 |  
  | 1931 | 872 | 2147 | (67) | 0 |  
  | 1932 | 824 | 2161 | (71) | 0 |  
  | 1933 | 781 | 2176 | (72) | 0 |  
  | 1934 | 712 | 2191 | (71) | 0 |  
  | 1935 | 668 | 2206 | (68) | 0 |  
  | 1936 | 589 | 2220 | (62) | 0 |  
  | 1937 | 518 | 2235 | (51) | 16 |  
  | 1938 | 515 | 2234 | (54) | 5 |  
  | 1939 | 443 | 2246 | (59) | 14 |  
 
Rating table notes
 | 
| Biographical data |  | 
   | Name: Guðmundsson, Jón |  
   | Born: |  
   | Died: |  |  |  
   | Notes: |  
   | Di Felice has 'Gudmundsson, Arinbjorn' at the Hamburg Olympiad 1930, but it should be Jón Gudmundsson. |  |  |  |  
   | References |  | 
| Books |  
   | Di Felice, Chess Results, 1921-1930, page 294 |  
   | Di Felice, Chess Results, 1936-1940, page 355 |  
   | Gaige, Chess Personalia, page 153 |  
   | Woodger, Reuben Fine, page 350 |  | Web |  
   | Bartelski, Wojciech.  [3rd Chess Olympiad: Hamburg 1930 - Iceland] |  |  |