Objective methods in which climatology is considered are needed in the design of flight instruction programs. Weather conditions less than the minimum (LM) thresholds designated for Minimum Instructional Visual Flight Rules (MIVFR) were defined as those with <3 mi visibility, <1500 ft ceilings, and/or with surface wind speeds >25 kt. The climatology of the LM conditions for four two-hour flight periods during the spring, fall, and summer semesters at Purdue University was generated. The negative binomial distribution was used to develop the expected LM probability deciles, which, for a fixed level of controllable resources, were used to predict the maximum number of students that should be enrolled in each semester. In the general aviation flight technology program at Purdue University, it was found that with present class enrollments in Visual Flight Rules (VFR) flight training, all students could be expected to complete their scheduled flying hours during a semester, without considerable makeup flight instruction outside the normal class hours, in less than half of the years.