Jupiter rules Sagittarius naturally and will be in it’s own sign, empowering it even more and the section of your Astrological chart whereby Sagg is situation.
In your natal horoscope it will be one of 12, however you can experience Jupiter in two different signs within the same house depending on the cusp.
In my daughter’s case Sagg is in her 4th house and 5th house. Possible pregnancy or involvement with children. Luck in games of chance and expansion of creativity. Fun, fun and more fun while in the 5th house.
In my son’s case Sagg is in his 2nd house which is wonderful for financial increase and opportunities for such.
Not everyone knows their exact time of birth, and solar charts are used. In this case Jupiter is transitting the 10th house for a Pisces individual and this effect can be felt to some degree by all Pisces. Career rewards are a good possibility if you have worked for them.
One thing to note is that the Sun Sign and Rising Sign are viewed in the same category by many Astrologers being that the Rising Sign is the outward personae. Our experiences are external and internal (who we really are beneath our Rising Sign skin)
This is a very brief summary – Don’t you just love the picture of the Archer.