What dates does the Sun spend in Aquarius?

Roughly January 20 to February 18. These are tropical-zodiac dates, measured from the equinox rather than from the constellation of the same name, and the exact ingress moves by up to a day or so between years because the tropical year is not a whole number of days. If a birth falls within a day of either boundary, the sign has to be computed for that specific date and time - a fixed date table will get some of those cases wrong.

Which planet rules Aquarius?

Modern Western astrology assigns Uranus as the ruler of Aquarius, but the classical rulership is Saturn. The split dates to the discovery of the outer planets: Uranus was not visible to naked-eye astronomers, so every pre-telescope source uses Saturn. Both attributions appear on this site because traditional and modern techniques answer different questions, and mixing the two rulerships silently is how contradictory readings get produced.

What does it mean that Aquarius is a fixed air sign?

Aquarius belongs to the air triplicity, described as hot and moist, which it shares with Gemini and Libra. Fixed signs sit at the middle of a season, when it is most established. The pairing of one element with one modality is unique to each sign - twelve signs, four elements, three modalities - so air plus fixed identifies Aquarius and no other sign. Polarity is active, alternating around the zodiac so that every sign sits between its two opposites in polarity.

Which planets are strong or weak in Aquarius?

Sun is in detriment here. Exaltation and fall are a fixed table inherited from Hellenistic astrology, not a judgment computed from the chart: they say a planet is easier or harder to work with in that sign regardless of anything else in the figure. Detriment is simply the sign opposite the one a planet rules. A planet with no listed dignity in Aquarius is called peregrine, which means unaspected by dignity rather than weak.

What are the three decans of Aquarius?

0 to 10 degrees is subruled by Aquarius (Uranus); 10 to 20 degrees is subruled by Gemini (Mercury); 20 to 30 degrees is subruled by Libra (Venus). This is the triplicity system, where a sign's three decans go to the three signs of its own element in zodiacal order, starting with itself. A competing Chaldean system assigns decan rulers by planetary order instead and produces different rulers for the same degrees, so a decan reading is only meaningful once you know which of the two systems it came from.

Aquarius

01-20 - 02-18 · air · fixed · active

Dignities

Ruler: ♅ Uranus
Classical Ruler: ♄ Saturn
Detriment: ☉ Sun
Symbol: Water-Bearer

Hellenistic tradition

Aquarius is the diurnal domicile of Saturn in pre-1781 tradition. Fixed air, traditionally tied to communal frameworks.

Modern Western reading

Modern Western astrology assigns Uranus as ruler (post-1781). Associated with collective ideas, technology, and the unconventional.

Same element

Decans

Planets in Aquarius

Compatibility with all signs

All Aquarius compatibility detail →

Questions

What dates does the Sun spend in Aquarius?: Roughly January 20 to February 18. These are tropical-zodiac dates, measured from the equinox rather than from the constellation of the same name, and the exact ingress moves by up to a day or so between years because the tropical year is not a whole number of days. If a birth falls within a day of either boundary, the sign has to be computed for that specific date and time - a fixed date table will get some of those cases wrong.
Which planet rules Aquarius?: Modern Western astrology assigns Uranus as the ruler of Aquarius, but the classical rulership is Saturn. The split dates to the discovery of the outer planets: Uranus was not visible to naked-eye astronomers, so every pre-telescope source uses Saturn. Both attributions appear on this site because traditional and modern techniques answer different questions, and mixing the two rulerships silently is how contradictory readings get produced.
What does it mean that Aquarius is a fixed air sign?: Aquarius belongs to the air triplicity, described as hot and moist, which it shares with Gemini and Libra. Fixed signs sit at the middle of a season, when it is most established. The pairing of one element with one modality is unique to each sign - twelve signs, four elements, three modalities - so air plus fixed identifies Aquarius and no other sign. Polarity is active, alternating around the zodiac so that every sign sits between its two opposites in polarity.
Which planets are strong or weak in Aquarius?: Sun is in detriment here. Exaltation and fall are a fixed table inherited from Hellenistic astrology, not a judgment computed from the chart: they say a planet is easier or harder to work with in that sign regardless of anything else in the figure. Detriment is simply the sign opposite the one a planet rules. A planet with no listed dignity in Aquarius is called peregrine, which means unaspected by dignity rather than weak.
What are the three decans of Aquarius?: 0 to 10 degrees is subruled by Aquarius (Uranus); 10 to 20 degrees is subruled by Gemini (Mercury); 20 to 30 degrees is subruled by Libra (Venus). This is the triplicity system, where a sign's three decans go to the three signs of its own element in zodiacal order, starting with itself. A competing Chaldean system assigns decan rulers by planetary order instead and produces different rulers for the same degrees, so a decan reading is only meaningful once you know which of the two systems it came from.

Reference, not advice

This is cultural and astronomical reference, not personal prediction or advice.

Tropical zodiac dates are astronomical conventions. Traditional interpretations are paraphrased from primary classical and modern sources. See sources and methodology.

Sources

Last reviewed 2026-05-28.