Solar months
How Sankranti marks the solar months
A Sankranti is the moment the Sun enters a sidereal sign. See how twelve Sankrantis make the solar months and how they decide the extra lunar month.
01 · Two calendars, one year
Sankrantis cut the solar months; new Moons cut the lunar ones.
A Sankranti is the moment the Sun enters a sidereal sign, and a solar month runs from one to the next. A lunar month runs from one new Moon to the next. The two calendars drift past each other, and the Sankranti inside each lunar month gives it its place in the year.
From 17 May to 15 June 2026 no Sankranti falls inside the lunar month, so it repeats the name of the month that follows and is counted as an extra month, Adhika Jyeshtha.
02 · Uneven months
Solar months are longer in mid-year.
Earth’s orbit is slightly elliptical. In early January Earth is nearest the Sun and the Sun moves fastest against the stars, so it crosses a sign in fewer days; in early July it moves slowest.
The Sun crossing a line
A Sankranti (संक्रान्ति) is the moment the Sun’s sidereal longitude reaches the start of a sign: the Sun’s own sign ingress. There are twelve a year, each named after the sign entered. Mesha Sankranti is the Sun’s entry into Aries; Makar Sankranti its entry into Capricorn.
Like every ingress, a Sankranti is one instant for the whole world, written in local clock time. In 2026 the Sun entered sidereal Capricorn at 14:44 IST on 14 January and sidereal Aries at 09:09 IST on 14 April. The next Makar Sankranti falls at 20:47 IST on 14 January 2027.
The day on which the festival is kept depends on regional rules about where in the day that moment falls. The moment itself is shared.
Solar months
A solar month runs from one Sankranti to the next, while the Sun crosses one sign. Because Earth’s orbit is slightly elliptical, the Sun moves fastest against the stars in early January and slowest in early July. Solar months are therefore shortest around the turn of the year and longest in mid-year: in 2026 they ranged from about 29.4 days, for Sagittarius, to about 31.4 days, for Gemini. The twelve signs article shows the same effect over 2026 to 2036.
Several regional calendars in India count their months from Sankranti to Sankranti, and some regional New Year festivals in mid-April mark Mesha Sankranti.
Makar Sankranti and the solstice
The Sun turns north at the December solstice, when it enters tropical Capricorn: 22 December in 2026. Makar Sankranti, its entry into sidereal Capricorn, now comes about 23 days later. The gap is the ayanamsa: the two Capricorns are 24° apart, and the gap grows by about a day every 72 years, as why the equinox drifts explains.
How Sankrantis fit the lunar months
A lunar month runs from new Moon to new Moon, about 29.5 days, a little shorter than an average solar month. Usually one Sankranti falls inside each lunar month, and the Sankranti it contains gives the month its place in the year.
Because lunar months are shorter, the Sankrantis slowly slide later within them. Every two or three years a lunar month passes with no Sankranti at all. That month takes the name of the month after it and is counted as an extra, Adhika (अधिक), month. In 2026 the lunar month from 17 May to 15 June held no Sankranti: the Sun entered Taurus on 15 May, two days before it began, and Gemini on 15 June, four hours after it ended. It was Adhika Jyeshtha, followed by the regular Jyeshtha.
Very rarely a lunar month contains two Sankrantis, and the calendar drops a month instead.
See the current lunar month on the Delhi Panchang, or explore another topic in Learn.