January zodiac sign: Capricorn, then Aquarius

January birthdays: Saturn's month

January opens deep inside Capricorn season, which began at the December solstice, and closes in Aquarius. Both signs were ruled by Saturn in traditional astrology, so January is the one month of the year that belongs to a single planet from start to finish. Saturn is the planet of time, structure and long effort, and it is a neat coincidence that the month of new year resolutions sits under it.

The two signs use Saturn very differently. Capricorn, cardinal earth, builds structures that last: careers, institutions, savings, reputations. Aquarius, fixed air, builds systems of ideas: communities, causes, inventions. Modern astrology gives Aquarius a second ruler, Uranus, the planet of sudden change, which is why the second half of January reads as more rebellious than the first.

Capricorn in January, Aquarius in January

January Capricorns are in the sign's second and third decans, ruled by Mars and the Sun in the old Chaldean order and read as the most driven and the most visible slices of the sign. January Aquarians are in its first decan, ruled by Venus in the old Chaldean order, the friendliest and most sociable slice of Aquarius.

• ✦Capricorn, January 1 to 19: ambitious, disciplined, dry humor, plays the long game.
• ✦Aquarius, January 20 to 31: independent, original, friendly with everyone, thinks ahead.
• ✦Both: principled, reserved at first, loyal once you are in.

January zodiac signs, day by day

On the US Eastern clock, January 1 to 18 is always Capricorn and January 21 onward is always Aquarius. In between is the change: from 1970 to 2035 the Sun entered Aquarius on January 20 in 43 of the 66 years and January 19 in 23. On the change day itself, a birth before the moment in the year table below is Capricorn and a birth after it is Aquarius.

When Aquarius begins each year, in Eastern time

The Sun's entry into Aquarius slides about six hours later each year and jumps back after a leap day. The next two are January 20, 2027 at 2:30 am Eastern, then January 20, 2028 at 8:20 am Eastern. Times are good to within 15 minutes. For Central time take one hour off, for Mountain two and for Pacific three, which can move the change to the day before; the sign page lists the same moments in UTC.

What else January birthdays share

The traditional January birthstone is the garnet, a deep red stone long linked with protection and steady friendship, which suits two signs known for loyalty. In the Northern Hemisphere January is the coldest stretch of the year and the light is only starting to return, an image astrologers use for both signs: Capricorn endures the winter, Aquarius imagines the spring.

January 20 is also US Inauguration Day, so presidential terms start on or a day after the Capricorn and Aquarius cusp. Martin Luther King Jr. Day, the third Monday of January, falls between January 15 and 21 and can land on either side of it.

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