53-week years: the trap that unbalances custody
Most years have 52 weeks. Some have 53, and that calendar detail has a very concrete consequence for separated parents: one parent keeps the children for two weeks in a row over New Year.
Why 53 weeks
A calendar year has 365 days — 52 weeks and one day, or two days in a leap year. Those surplus days eventually add up to an extra week. In practice, a year has 53 weeks when 1 January falls on a Thursday, or on a Wednesday in a leap year.
It comes round roughly every five to six years, irregularly: 2015, 2020, 2026, 2032, 2037.
What it does to an even/odd rhythm
Week 53 is odd. Week 1 of the following year is odd too. Two odd weeks therefore run back to back, and the parent holding the odd weeks keeps the children for fourteen consecutive days.
At the end of 2026, that double week runs from Monday 28 December 2026 to Sunday 10 January 2027. Across the year, that parent gets 27 weeks against 26 for the other.
How to handle it
Three approaches appear in parenting agreements:
- Do nothing and let the double week happen, offsetting it at the next long year — the imbalance then reverses on its own.
- Swap the rhythm on 1 January of the following year: whoever had the even weeks takes the odd ones, which rebalances immediately.
- Neutralise week 53 by assigning it explicitly to the other parent in the agreement.
Whichever option is chosen, the essential thing is that it is written down. A double week discovered on 28 December, with no rule in place, is a classic source of conflict.
Our schedule generator flags these runs automatically and gives you the exact dates.