Why the school calendar drives meal planning
Family meal planning lives or dies on knowing what each evening looks like: who is home, who is at practice, who has homework deadlines, who needs an early dinner. The published school calendar is the input to all of this, and a printed calendar is the most efficient surface to lay a meal plan on top of.
The weekly pass
Most meal planners do a weekly pass: every Sunday afternoon, look at the upcoming week's printed calendar, decide on five evening meals, and write them in. The decision benefits enormously from the printed calendar showing the school events: a parent-teacher conference on Wednesday probably means a quick-prep meal that evening; a home volleyball game on Tuesday means an early dinner; a half-day Friday means a relaxed family dinner.
The monthly pass
For larger households, a monthly meal-planning pass is more efficient than weekly. Print the upcoming month on the first weekend of the previous month, mark the standing weekly pattern (Mexican Mondays, pasta Wednesdays, leftover Fridays), then overlay the school events that disrupt the pattern. The result is a single page that drives the grocery list and the family schedule for the entire month.
Holiday cooking
The federal holidays on the school calendar are also the major holiday-cooking days: Thanksgiving in November, the Christmas-and-New-Year stretch in December and January, Easter in March or April, Memorial Day in May, and Independence Day in July. Mark the holiday-cooking days on the printed calendar in advance so the grocery shopping for them doesn't collide with the regular weekly shopping.
The school-lunch question
For families that pack school lunches, the printed school calendar drives the lunch-prep schedule too. Mark the days where school provides lunch (often the first day, picture day, party days) so they don't get accidentally double-packed. The printed reference is much faster than checking the school's published menu every morning.