8 minlater bedtime on Saturdays than on weekdays. Babies barely notice the weekend.
Family schedules loosen a little on Friday and Saturday evenings, but babies' days stay remarkably steady across the week. The weekly rhythm is tiny compared with the spread in bedtimes between families.
Complete days rebuilt from parents' own logs (a day counts when a parent logged the wake-up, every nap and bedtime), babies aged 3 to 18 months, local time, October 2025 to September 2026; no settled-routine filter. For each baby with at least 14 complete days, each day's bedtime and wake-up minus that baby's own average; averaged per weekday within baby, then across babies. Saturday bedtime +6.04 min vs Monday to Thursday average -2.01 min (8.1 min apart); Friday +2.74 min. Sunday wake-up +5.18 min vs Monday to Friday average -1.36 min (6.5 min apart). 370,993 babies, 47.6 million days.