Finding the real start of the year
The Chinese year begins at the second new moon after the December solstice. That puts new year's day somewhere in the six weeks from 21 January to 20 February, moving with the Moon. Recent boundaries include 5 February in 2000, 7 February in 2008, 29 January in 2025 and 6 February in 2027.
Most western tools ignore this and split the animals at 1 January, which gives the wrong animal to everyone born in that window, about one birthday in eight. The example to keep in mind is a birth on 1 February 1988. A Gregorian table calls it a Dragon; the 1988 new year fell on 17 February, so the real animal is Rabbit, from the closing weeks of the preceding year.
From late February onwards both methods agree, which is why the error is rarely spotted. The check above computes the boundary for the year you enter and places the date correctly.
Rooster years and their elements
The Rooster comes round every twelve years. Recent Rooster years are 1981, 1993, 2005 and 2017, and the next is 2029. Each year runs from its new year date to the day before the next, so it spans parts of two Gregorian years.
The five elements, Wood, Fire, Earth, Metal and Water, run underneath in pairs of years. Ten and twelve only agree again after sixty, so a particular animal and element pairing is a once in a lifetime event. 2017 was a Fire Rooster year; 2005 was a Wood Rooster. The element belongs in the year's name, and traditional readings weigh it as heavily as the animal, so a verdict quoted without it is only half the tradition's answer.
Only the animal and the element together identify a year in the traditional sense. Two Rooster years sixty years apart share a name; two twelve years apart do not.
The race, the polarity and what is read in
The Rooster is a yin animal. In the Great Race it crossed the river on the raft it built with the Goat and the Monkey, and stepped off last of the three, taking tenth place.
The traditional reading is of precision and visibility. The Rooster is described as punctual, observant, well turned out and unusually direct about what it notices, the kind of sign that says the thing everyone else is leaving unsaid. The same account calls it critical, blunt and inclined to fuss over detail that will not matter. Since the label attaches to an entire year of births, this is a description of a cohort rather than of a person, which is a good deal weaker than it is usually made to sound.
Trines, opposite, and the other zodiac
The Rooster belongs to the trine with the Ox and the Snake, animals four places apart and read as methodical, exacting and slow to change direction once set. Six places away is the Rabbit, the Rooster's opposite, described as bluntness meeting a preference for smooth surfaces. Traditional practice looks at the elements of both years before saying anything firm about a match.
Finally, the systems question. Chinese and western astrology are unrelated. One assigns an animal from the year of birth in a lunisolar calendar; the other assigns a sign from the Sun's position on a particular day of a solar year. They are not two accounts of the same underlying thing, they do not need reconciling, and neither one is evidence for the other.
What would change a traditional verdict on a match is the element pairing rather than anything about the people involved, which is a fair indication of how the system works.
Questions people ask about this
When was the last Rooster year?
2017, opening at the lunisolar new year in late January rather than on 1 January. The one before it was 2005, and the next Rooster year is 2029.
What element was the 2017 Rooster?
Fire. The 2005 Rooster year carried Wood, since the element cycle moves through Wood, Fire, Earth, Metal and Water in blocks of two years.
Does a February birthday need checking?
Yes, up to 20 February. New year has fallen as late as 17 February in recent years, so early February births can belong to either of two animals depending on the year.
Why is the Rooster tenth?
By the usual telling it helped build the raft that carried the Goat, the Monkey and itself across the river, and came ashore last of the three.
Which animals suit the Rooster?
Its trine is the Ox and the Snake, read as a set that shares a taste for order. The tradition also weighs the element of each year before treating the match as settled.
Can I combine my Rooster year with my Sun sign?
They can be held side by side, but nothing links them. One depends on the lunisolar year and the other on the solar day, so combining them adds no information.