Colorado law requires school districts to schedule 1080 hours per year of instructional time for secondary schools and 990 instructional hours for elementary schools. The 1080 hours equate to six hours per day for 180 days. The 990 hours equate to five and one-half hours per day. Up to 24 hours may be counted for parent-teacher conferences, staff in-service programs, and closing for reasons of health, safety, or welfare of students. The law also requires any district offering less than 160 days of school to obtain permission from the Commissioner of Education. Sixty-two school districts, constituting 34% of the 178 school districts in Colorado, serving 2.7% of students, utilize the four-day week as the structure for organizing their school year. Those districts schedule 7.5 hours per day for 144 days of school instead of the normal six hours for 180 days. In some cases, only a few of the district schools are on a four-day week. For example, in Moffat County RE-1, only Maybell Elementary is on a four-day week. In Mesa County Valley 51, only New Emerson School is on a four-day week. This paper presents observations based on extensive conversations with practitioners in four-day districts and visitations to most of those districts. The impact of the shift to the four-day week as it relates to finance, child care, instruction, politics, and student performance are discussed.