The moon is reaching its orbital limits every 18.6 years

Space · Published 25 October 2026 Swipe more like this →

In short: Every nearly two decades, the Moon performs a celestial extreme. At its orbital limits, it appears on the horizon at maximum northern and southern latitudes. This rare event creates dramatic lunar displays that have intrigued humans for millennia.

An 18.6-year cycle of the Moon's tilted path creates the periodic Major Lunar Standstill. During this time, the northernmost and southernmost moonrise and moonset points are at their maximum distance from one another. While the peak of this specific event occurs in January 2025, the 'season' for observing these extremes lasts for about two years. The phenomenon is caused by the rotation of the Moon’s inclined orbit over this specific timeframe. This cycle means that every 27 days during the standstill season, the moon reaches its northernmost and southernmost extremes. These events are not limited to a single day but span a significant period.

For observers on Earth, the Moon appears to reach its highest and lowest altitudes during this window. Because the greatest monthly excursion changes very little during a standstill, the phenomenon remains observable throughout much of 2024 and into 2025. While it can be seen from any location on Earth—unlike an eclipse—the most dramatic displays occur when these extreme points coincide with specific lunar phases, particularly near the solstices. The full moon provides the most spectacular viewing experience for these lunar movements. In some southern locations with high mountains, the moon might only appear briefly or seem to roll across the hills due to its low altitude. Conversely, it may not be visible at all in certain terrains.

The event carries significant historical weight, as researchers are currently investigating whether ancient monuments like Stonehenge were designed with these specific orbital extremes in mind. Because the Moon reaches these limits every 18.6 years, it provides a rare opportunity to study how prehistoric civilizations may have tracked complex celestial mechanics through architectural alignment. Archaeologists are currently exploring how this cycle influenced the construction of famous prehistoric sites. Specific dates for these events have been identified, including a notable southern moonrise on May 14, 2025. The Griffith Observatory even features inlaid lines to help viewers track these specific moonset positions.

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