Significance
Uttarayan marks the Sun's transition into Capricorn and the beginning of its northward (uttar) journey — the same solar event as Makar Sankranti. In Gujarat it is celebrated as the exuberant International Kite Festival.
The northward course of the Sun (Uttarayan) is considered a highly auspicious period, favoured for spiritual undertakings.
Rituals
The skies fill with countless colourful kites as families spend the day on rooftops in friendly kite-fighting, calling "kai po che!" Traditional treats like undhiyu, chikki and til-laddu are shared, and holy dips and charity mark the sacred transit.
How the date is fixed
Uttarayan is a solar festival set by the Sun's entry into sidereal Capricorn — around 14–15 January — so its date is nearly fixed; the punya kaal above is for your location.