Tropical Zodiac

The Tropical Zodiac is the system of zodiac signs used in Western astrology. It divides the ecliptic into twelve equal signs of 30° each, starting at 0° Aries, which is defined by the March equinox (when day and night are equal). Unlike the Sidereal Zodiac, which is fixed to the constellations, the Tropical Zodiac is tied to the seasons. This means that the signs correspond to the Earth's relationship to the Sun over the course of the year, not to the actual positions of the stars.

How it works

In a natal chart, the Tropical Zodiac is the default for most Western astrologers. The Sun enters Aries at the spring equinox (around March 20), Cancer at the summer solstice, Libra at the autumnal equinox, and Capricorn at the winter solstice. Because of the precession of the equinoxes, the Tropical Zodiac has drifted about 24° from the Sidereal Zodiac over the past 2,000 years. This means that someone who is a Tropical Aries might be a Sidereal Pisces. The choice between systems is a matter of tradition and interpretive preference.

In practice

When reading a chart using the Tropical Zodiac, the focus is on seasonal symbolism. For example, Aries energy is about initiation and springtime, while Libra is about balance and harvest. The planets and houses are interpreted within this seasonal framework. Most online chart calculators, including the one at Astraly, use the Tropical Zodiac by default. If you are comparing charts with someone who uses the Sidereal system, the sign placements will differ, but the aspects and house positions remain valid within each system.