Eclipse seasons
Why there is no eclipse every month
The Moon passes the Sun every month, yet eclipses come only in two short seasons a year. See how the tilt of its orbit and the nodes decide when.
01 · A year of new and full Moons
Most months, the Moon passes above or below.
At every new Moon the Moon is in the Sun’s direction, and at every full Moon it is opposite. Its tilted orbit usually carries it a few degrees north or south of the exact line, so the Sun is not covered and Earth’s shadow is missed. Step through 2026.
The points never stray more than about 5° from the ecliptic, the tilt of the Moon’s orbit. They cross the eclipse band only twice in the year, in February to March and in August, and both times two eclipses came two weeks apart.
02 · Close to a node
Distance from a node decides it.
The Moon crosses the ecliptic at its two nodes, Rahu and Ketu. The nearer a new or full Moon falls to one of them, the closer it lies to the ecliptic. Over eleven years, that one distance sorts every eclipse from every miss.
03 · Eclipse seasons
Eclipses come in seasons, a little earlier each year.
The Sun passes each node once a year, so the window opens twice. The nodes drift backwards about 19° a year, so the Sun reaches them a little sooner each time, and the seasons slide through the calendar.
A tilted path
The Moon passes between Earth and the Sun at every new Moon, and lies opposite the Sun at every full Moon, about 12 or 13 times a year each. If its orbit lay flat in the plane of Earth’s orbit, every new Moon would cover the Sun somewhere on Earth and every full Moon would pass through Earth’s shadow.
The orbit is tilted by about 5.1° to the ecliptic. At a new or full Moon the Moon can therefore be anywhere from exactly on the ecliptic to about 5° north or south of it. Both the Sun and the Moon appear only about half a degree across, so a miss of a few degrees is a wide one.
To give an eclipse, the Moon needs to be within roughly 1.5° of the ecliptic at a new or full Moon. That margin is wider than the Sun’s own half-degree for two reasons. Observers spread across Earth see the Moon from slightly different directions, so a solar eclipse needs to happen for only some of them. And Earth’s shadow, including its faint outer part, is wider than the Moon. The exact limit shifts a little with the distances of the Sun and Moon.
How close to a node
The Moon’s path crosses the ecliptic at two points, its nodes, which Indian astronomy names Rahu and Ketu. At a node the Moon is on the ecliptic; a quarter of the way round, it is about 5° away. In between, its distance from the ecliptic depends on how far it is from the nearer node.
That single distance decides eclipses. Between 2026 and 2036 there are 272 new and full Moons. Every eclipse among them falls within 17.5° of a node, and every new or full Moon without one falls more than 18° away. The 50 eclipses split evenly: 25 solar and 25 lunar. Of the lunar ones, 16 are partial or total, all within 12° of a node; the rest are penumbral, where the Moon passes only through the faint outer edge of Earth’s shadow.
Eclipse seasons
The Sun passes each node once a year. While it is within about 17° of one, any new or full Moon falls close enough to the node for an eclipse. The Sun takes more than a month to cross that window, longer than the 29.5 days between new Moons, so at least one new Moon always lands inside it. Every eclipse season therefore has at least one solar eclipse, and every year at least two.
A season often holds two eclipses two weeks apart, one at a new Moon and one at the full Moon either side. In 2026 the annular solar eclipse of 17 February was followed by the total lunar eclipse of 3 March, and the total solar eclipse of 12 August by the partial lunar eclipse of 28 August. A wide window can even catch two new Moons: 2029 has four solar eclipses, all partial.
The seasons come about 173 days apart, not exactly half a year. The nodes drift backwards along the ecliptic by about 19° a year, so the Sun meets each one a little sooner every time. As a result the eclipse seasons slide earlier through the calendar, from February and August in 2026 to January and July in 2028 and December and June by 2029 and 2030. Each year from 2026 to 2036 has between four and six eclipses, counting penumbral ones.
In the Panchang
A solar eclipse always comes at a new Moon, the end of Amavasya, and a lunar eclipse at a full Moon, the end of Purnima. Only a few of each year’s Amavasya and Purnima tithis bring one, the ones that fall in an eclipse season. Whose shadow falls where explains the two kinds of eclipse and who can see each.
See the dates of Amavasya in 2026 and Purnima in 2026, or explore another topic in Learn.