Virgo

Virgo (♍) is the sixth astrological sign in the Zodiac, originating from the constellation of Virgo. In western astrology, the sign is no longer aligned with the constellation as a result of the precession of the equinoxes. In astrology, Virgo is considered a "feminine", negative (introvert) sign. It is also considered an earth sign and is one of four mutable signs. Virgo is traditionally ruled by the planet Mercury, but Ceres and several other planets have been suggested as the ruler of Virgo by some modern astrologers. Being the sixth sign of the zodiac, Virgo has been associated with the astrological sixth house.
Individuals born when the Sun was in this sign are considered Virgo individuals. Under the tropical zodiac, the Sun is in Virgo roughly from August 23 to September 22, leaving it at the moment of autumnal equinox, by definition. Under the sidereal zodiac, it is currently there roughly from September 17 to October 17. The Sanskrit name of Virgo in Hindu astrology is Kanyā (Girl).

Compatibilities
Based on Elements within the Zodiac, Virgo is considered compatible with Taurus, Capricorn, and Virgo itself.
There are many variables that determine compatibility in astrology, such as birth dates, birth months, birth years, position of a sign within the Sun, the Moon, Stars, etc. The signs listed as compatible with Virgo do not reflect an individual profile or individual reading as interpreted within astrology, but rather reflect a general guideline and reference to compatibility as dictated by variables such as Qualities and Elements within the Zodiac. The branch of astrology dealing with non-interpersonal compatibilities is called Synastry.
source : http://en.wikipedia.org/wiki/Virgo

What is Synastry

Astrological compatibility (synastry) is the branch of astrology that studies relationships by comparing natal horoscopes. A natal horoscope is a chart, map, or imaginary snapshot of the planets in the Solar System and their positions in the zodiac at the exact time of a person's birth. The signs of the Zodiac represent 12 different types of spiritual energy and purpose. The planets in the Solar System are associated with at least one, but most often two signs of the zodiac.

Relationships between planets, signs (types of energy), and houses (sectors of the chart) are described in words and /or often rated in numbers to show to what degree, how, and in what ways one person is compatible or incompatible with another. The assessment is based on the patterns and distributions of energy in the respective and combined charts.

Compatibility between Zodiac signs is always approached within a particular branch of astrological tradition: Chinese astrology, Western astrology or Vedic astrology.
Source : http://en.wikipedia.org/wiki/Synastry

Leo

Leo (♌) is the 5th astrological sign of the Zodiac, originating from the constellation of Leo. In astrology, Leo is considered to be a "masculine", positive (extrovert) sign. It is also considered a fire sign and is one of four fixed signs. Leo is ruled by the Sun. Being the fifth sign of the zodiac, Leo has been associated with the astrological fifth house.

Individuals born when the Sun was in this sign are considered Leo individuals. The Sun is in Leo roughly from July 23 to August 22. Under the sidereal zodiac, it is currently there roughly from August 10 to September 15. The Sanskrit name of Leo in Hindu astrology is Siṃha.

Compatibilities
Based on Elements within the Zodiac, Leo is considered compatible with Aries, Sagittarius and Leo itself.
There are many variables that determine compatibility in astrology, such as birth dates, birth months, birth years, position of a sign within the Sun, the Moon, Stars. The signs listed as compatible with Leo do not reflect an individual profile or individual reading as interpreted within astrology, but rather reflect a general guideline and reference to compatibility as dictated by variables such as Qualities and Elements within the Zodiac. The branch of astrology dealing with interpersonal compatibilities is called Synastry.
Source : http://en.wikipedia.org/wiki/Leo

Cancer

Cancer (♋) is the fourth astrological sign in the Zodiac, originating
from the constellation of Cancer. In western astrology, this sign is no longer aligned with the constellation as a result of the precession of the equinoxes. In astrology, Cancer is considered a "feminine", negative (introvert) sign. It is also considered a water sign and is one of four cardinal signs. Cancer is ruled by the Moon. Being the fourth sign in the zodiac, Cancer has been associated with the astrological fourth house.

Individuals born when the Sun was in this sign are considered Cancer individuals. Under the tropical zodiac, the Sun enters Cancer on the moment of summer solstice by definition, or roughly on June 22, leaving it around July 23. Under the sidereal zodiac, it is currently roughly from July 16 to August 15. The Sanskrit name of Cancer in Hindu astrology is Karka.

Compatibilities
Based on Elements within the Zodiac, Cancer is considered compatible with Scorpio, Pisces and Cancer itself.
There are many variables that determine compatibility in astrology, such as birth dates, birth months, personalities, birth years, position of a sign within the Sun, the Moon, Stars, etc. The signs listed as compatible with Cancer do not reflect an individual profile or individual reading as interpreted within astrology, but rather reflect a general guideline and reference to compatibility as dictated by variables such as Qualities and Elements within the Zodiac. The branch in astrology dealing with interpersonal compatibilities is called Synastry.
Source : http://en.wikipedia.org/wiki/Cancer

Gemini

Gemini (♊) is the third astrological sign in the Zodiac, originating from the constellation of Gemini. In western astrology, this sign is no longer aligned with the constellation as a result of the precession of the equinoxes. In astrology, Gemini is considered a "masculine", positive (extrovert) sign. It is also considered an air sign, and is one of four mutable signs. Gemini has been closely associated with the planet Mercury and is considered to be ruled by it. Being the third sign of the zodiac, Gemini has been associated with the astrological third house.

Individuals born when the Sun was in this sign are considered Gemini individuals. Under the tropical (western) zodiac, the Sun is in the sign of Gemini roughly from May 21 to June 22, ending at the moment of summer solstice by definition. Under the sidereal zodiac, it is currently there roughly from June 15 to July 15. The Sanskrit name of Gemini in Hindu astrology is Mithuna.

Compatibilities
Generally, Gemini is considered compatible with Libra, Aquarius and Gemini itself. These signs share an "airy" demeanor and are believed to relate on that merit.
There are many variables in the astrology chart that determine compatibility of individuals. The position of the Sun, the Moon, the planets and the aspects they form with each other are assessed by astrologers before judgment on compatibility is made. The signs listed as compatible with Gemini do not reflect an individual profile or individual reading as interpreted within astrology, but rather reflect a general guideline and reference to compatibility as dictated by variables such as Qualities and Elements within the Zodiac. The branch of astrology dealing with interpersonal compatibilities is called Synastry.
Source : http://en.wikipedia.org/wiki/Gemini