In Vedic Astrology, Surya (the Sun) is the Atmakaraka, the significator of the soul, vitality, and authority. Its transit (Sankranti) through the 12 zodiac signs (Rashis) marks the solar months, influencing not just seasonal changes but also personal energy, career, relationships, and well-being. Each transit lasts approximately 30 days, with the Sun entering a new sign around the 14th–15th of each Gregorian month. This movement aligns with the rising zodiac sign (Lagna) at sunrise, creating unique daily dynamics based on the Sun's house position relative to the rising sign.
Drawing from classical texts like Brihat Parashara Hora Shastra, the Sun's position at sunrise sets the tone for the day. For instance, when the Sun transits Aries from April 15 to May 14, Aries rises at sunrise, placing the Sun in the 1st house (Lagna). This pattern shifts monthly, affecting how the Sun's energy manifests in various houses.