ORDINARY EFFORT is the effort that a fielder of average skill at a position in that league or classification of leagues should exhibit on a play, with due consideration given to the condition of the field and weather conditions.
Rule 2.00 (Ordinary Effort) Comment: This standard, called for several times in the Official Scoring Rules (e.g., Rules 10.05(a)(3), 10.05(a)(4), 10.05(a)(6), 10.05(b)(3) (Base Hits); 10.08(b) (Sacrifices); 10.12(a)(1) Comment, 10.12(d)(2) (Errors); and 10.13(a), 10.13(b) (Wild Pitches and Passed Balls)) and in the Official Baseball Rules (e.g., Rule 2.00 (Infield Fly)), is an objective standard in regard to any particular fielder. In other words, even if a fielder makes his best effort, if that effort falls short of what an average fielder at that position in that league would have made in a situation, the official scorer should charge that fielder with an error.
Outside of Rule 10, the term "ordinary effort" only appears in the context of an infield fly and wild pitch. For umpires, ordinary effort has only one application: the infield fly rule.
Weather conditions are a factor (wind, rain), but sun and darkness are not factors. For instance, losing sight of a ball when it passes above the lights is not a consideration in determining an infield fly. [J/R]
Bases loaded, 1 out. Batter hits infield fly, but F4 loses ball in the sun and it drops. Umpire rules catch could be made with ordinary effort. The sun is not a weather condition.