Seats on the third base side at Petco Park are the best options to find seats with shade. The 200 level and seats in the back portion of the 100 level on the third base side will have the most shade throughout the afternoon. The upper level on the third base side is also not a bad option because the sun will be behind you in the afternoon. Avoid seats in right field, especially on the 200 level, as these seats are likely to be in the sun for much of the game.