Due to the change of the earth's axis and the movement of solar system and stars, the current positions of zodiac signs are different with that of 2000 years ago. A month-by-month summary table is available at the bottom of the page. Now, the date of zodiac signs have changed and it is no longer consistent with the astronomical phenomenon. Aries (March 21 - April 20) is the first sign of the zodiac and Pisces (February 19 - March 20) the last. In 1982, the international astronomical conference modified the constellation range and approved Ophiuchus as the thirteenth onstellation. The zodiac year starting at the spring equinox, we have listed the twelve signs of the zodiac by respecting the order of the astrological houses. The huge Scorpio also needs to be redesigned, perhaps only including people born on between November 23 and 29 while people born on between November 29 and December 17 should be under the Ophiuchus rather than Sagittarius sign. If you think you are under the Aquarius sign, you might be a Piscean while the original Scorpian might be a Sagittarian. In addition to the twelve zodiac signs, the current ecliptic also spans the thirteenth constellation Ophiuchus which is located between Scorpio and Sagittarius.
As a result, the time of the Sun arriving at a constellation would delay about one month every 2000 years. Since the earth's axis swings in a circle of 26000 years, the ecliptic position also changes in the sky.