What dates does the Sun spend in Cancer?

Roughly June 21 to July 22. 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 Cancer?

Moon, in both the classical and the modern scheme. Cancer is one of the signs whose rulership was never reassigned after the outer planets were found, so traditional and modern sources agree here.

What does it mean that Cancer is a cardinal water sign?

Cancer belongs to the water triplicity, described as cold and moist, which it shares with Scorpio and Pisces. Cardinal signs open a season: the Sun enters one at each equinox or solstice. The pairing of one element with one modality is unique to each sign - twelve signs, four elements, three modalities - so water plus cardinal identifies Cancer and no other sign. Polarity is receptive, alternating around the zodiac so that every sign sits between its two opposites in polarity.

Which planets are strong or weak in Cancer?

Jupiter is exalted in Cancer, Mars is in fall here, Saturn 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 Cancer is called peregrine, which means unaspected by dignity rather than weak.

What are the three decans of Cancer?

0 to 10 degrees is subruled by Cancer (Moon); 10 to 20 degrees is subruled by Scorpio (Pluto); 20 to 30 degrees is subruled by Pisces (Neptune). 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.

Cancer

06-21 - 07-22 · water · cardinal · receptive

Dignities

Ruler: ☽ Moon
Exaltation: ♃ Jupiter
Fall: ♂ Mars
Detriment: ♄ Saturn
Symbol: Crab

Hellenistic tradition

Cancer is the sole domicile of the Moon and exaltation of Jupiter. Cardinal water, traditionally tied to nourishment and the household.

Modern Western reading

Modern Western astrology reads Cancer as associated with home, memory, and emotional security.

Same element

Decans

Planets in Cancer

Compatibility with all signs

All Cancer compatibility detail →

Questions

What dates does the Sun spend in Cancer?: Roughly June 21 to July 22. 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 Cancer?: Moon, in both the classical and the modern scheme. Cancer is one of the signs whose rulership was never reassigned after the outer planets were found, so traditional and modern sources agree here.
What does it mean that Cancer is a cardinal water sign?: Cancer belongs to the water triplicity, described as cold and moist, which it shares with Scorpio and Pisces. Cardinal signs open a season: the Sun enters one at each equinox or solstice. The pairing of one element with one modality is unique to each sign - twelve signs, four elements, three modalities - so water plus cardinal identifies Cancer and no other sign. Polarity is receptive, alternating around the zodiac so that every sign sits between its two opposites in polarity.
Which planets are strong or weak in Cancer?: Jupiter is exalted in Cancer, Mars is in fall here, Saturn 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 Cancer is called peregrine, which means unaspected by dignity rather than weak.
What are the three decans of Cancer?: 0 to 10 degrees is subruled by Cancer (Moon); 10 to 20 degrees is subruled by Scorpio (Pluto); 20 to 30 degrees is subruled by Pisces (Neptune). 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.