2027 holiday odds for rotation workers
How often does each repeating roster put every day of a holiday period on scheduled rest? We test every possible phase, not a randomly chosen start date.
Chance of being rostered off for the entire period
Christmas: 24–26 Dec 2027 · New Year: 31 Dec 2027–1 Jan 2028 · Easter: 26–29 Mar 2027 (Good Friday through Easter Monday).
| Rotation | Christmas | New Year | Easter |
|---|---|---|---|
| 14/14 | 42.9% (12/28) | 46.4% (13/28) | 39.3% (11/28) |
| 7/7 | 35.7% (5/14) | 42.9% (6/14) | 28.6% (4/14) |
| 8/6 | 28.6% (4/14) | 35.7% (5/14) | 21.4% (3/14) |
| 21/7 | 17.9% (5/28) | 21.4% (6/28) | 14.3% (4/28) |
| 2/1 (weeks) | 23.8% (5/21) | 28.6% (6/21) | 19.0% (4/21) |
| 14/21 | 54.3% (19/35) | 57.1% (20/35) | 51.4% (18/35) |
| 21/21 | 45.2% (19/42) | 47.6% (20/42) | 42.9% (18/42) |
| 28/28 | 46.4% (26/56) | 48.2% (27/56) | 44.6% (25/56) |
| 24/48 (hours) | 0.0% (0/3) | 33.3% (1/3) | 0.0% (0/3) |
| 48/96 (hours) | 33.3% (2/6) | 50.0% (3/6) | 16.7% (1/6) |
Illustrative school summer windows: average rostered rest dates
These are intentionally fixed study windows, not official school calendars for entire countries. AU: 20 Dec 2027–30 Jan 2028; UK: 19 Jul–29 Aug 2027; US: 15 Jun–15 Aug 2027. States, districts, schools and years differ.
| Rotation | AU example (42 days) | UK example (42 days) | US example (62 days) |
|---|---|---|---|
| 14/14 | 21.0 | 21.0 | 31.0 |
| 7/7 | 21.0 | 21.0 | 31.0 |
| 8/6 | 18.0 | 18.0 | 26.6 |
| 21/7 | 10.5 | 10.5 | 15.5 |
| 2/1 (weeks) | 14.0 | 14.0 | 20.7 |
| 14/21 | 25.2 | 25.2 | 37.2 |
| 21/21 | 21.0 | 21.0 | 31.0 |
| 28/28 | 21.0 | 21.0 | 31.0 |
| 24/48 (hours) | 28.0 | 28.0 | 41.3 |
| 48/96 (hours) | 28.0 | 28.0 | 41.3 |
Methodology and interpretation
For each pattern with W consecutive duty days and R consecutive rest days, we enumerate every integer phase offset from zero to W+R−1. Every offset receives equal weight. A date counts as rostered rest when its repeating phase falls in the R-day block. The probability for a holiday period is the share of offsets where all its dates are rest dates. Summer results average the number of rest dates over all offsets. This is a mathematical phase comparison, not a prediction of someone’s actual assignment or employer leave policy.
For example, the Christmas period contains three dates. In a 14/14 roster, exactly twelve of twenty-eight phases keep all three dates off: 42.9%. Night duty, travel, Kelly days, overtime, shift changes, public holiday treatment and leave are deliberately excluded. A 24/48 duty/rest pattern is represented as one 24-hour duty date followed by two rest dates. The New Year period crosses into 2028 without restarting the roster. Actual chances are not random if an employer assigns particular rotations or holidays systematically.
Interpret the percentages as counts of possible schedule phases, not a measured population survey. This exercise cannot tell you what fraction of real firefighters or offshore crews will be home. In practice, an employer may choose specific shift anchors, keep a crew on the same rotation for years, or deliberately adjust December staffing. Those choices violate the equal-phase assumption. The figures are nevertheless reproducible and useful for comparing the geometry of different cycles, as long as that assumption appears alongside each result.
Our all-days-off test is deliberately strict. Having one of the Christmas dates free does not qualify as the complete Christmas break. For someone who works an overnight shift, even a duty date counted as rest in a calendar-day abstraction might include recovery or travel. We deliberately avoid interpreting a shift as a paid hour, an approved holiday, or guaranteed time at home. The difference is especially important for 24/48 and 48/96: those labels refer to hours, but this model maps them onto whole 24-hour periods for consistent comparisons.
The summer comparisons use fixed illustrative lengths rather than official national school calendars. A UK school in one council area, a US school district in another state, and an Australian term schedule can have quite different break dates. Counting rostered rest dates over a fixed interval makes the mathematics easy to reproduce but does not represent a promise about school dates in your locality. Enter exact local dates separately when arranging childcare, family travel or annual leave.
For family and travel decisions, your real first duty date matters more than any probability. Check your confirmed swing and compare two actual rosters.
Check your exact roster → · Compare partner days off → · 14/14 calendar → · 21/7 calendar → · 24/48 firefighter example →