An eclipse season is a string of 2 or 3 eclipses in a row.
Eclipse seasons exist because the Moon orbits the Earth at about a 5 degree angle and the Earth orbits the Sun at about a 23.45 degree angle. Because the orbits have different angles and the length of the orbits are not in phase with each other, it can take some time for the Sun, Earth, and Moon to misalign when they do eventually get in alignment.
The four possible eclipse seasons are as follows:
Eclipse seasons happen on average about every 6 months, so at least 2 eclipse seasons occur during each solar year, although it is possible for 3 eclipse seasons to occur during a solar year.