The effects of Moon being in the third house of the Lagna (ascendant) chart are somewhat debatable. However, one thing is for certain which also makes sense logically – whenever the Moon occupies the third house, which is the house of siblings, the person is more likely to have female siblings (sisters) than brothers.
Additionally, it is also stated that Moon’s presence in the third house is not very favorable for finances, unless Moon is in Her own sign (Cancer) or in exaltation (Taurus) or conjunct with a benefic planet.
Nonetheless, Moon will still give its usual benefits such as a good appearance and good relations with others.
One more thing – the third house also governs short journeys, so the person may feel happy when they take short journeys.
And lastly, because the third house represents siblings primarily, the native’s siblings may have Moon-like qualities – they too may be good looking and also be emotional. Alternatively, the Moon here also represents the connections or relations of the native with his/her siblings, which would be good overall with some arguments here and there because the Moon is overall a benefic planet.
As for malefic planets, it can be said that if Rahu is connected with the third house, then the person would have a tense relationship with their siblings but their siblings would be quite clever and intelligent (both qualities of Rahu).
Some texts also suggest that the third house controls intelligence, education up to the school level, writing, ornaments, and clothes. Moon, being a natural benefic, will boost all of those aspects except intelligence because it is the significator of emotions.
Some pointers here would be that:
- Moon is in a female zodiac sign (all even numbered signs are female zodiac signs) – the person is more likely to have sisters
- Moon is in a male zodiac sign (all odd numbered signs are male zodiac signs) – the person may have brothers if the lord of the 3rd house is also well placed or strong
Now, of course, if the Moon is not adjacent to any benefic planet, nor aspected or conjunct with any benefic planet, it will start suffering from loneliness once again. In such cases, the person may undertake short journeys (for example) to fix their loneliness, and that causes them to indulge more with the opposite gender.