When the Moon Stands Over the Kaaba, and Why It Cannot From 2032 to 2036

The Short Answer

The Sun passes straight over the Kaaba twice every year, as described in finding the Qibla from the Sun's shadow. The Moon is less regular. In most years it passes within half a degree of straight overhead at the Kaaba, about the width of the Moon itself, between 5 and 19 times. But from 2032 to 2036 it does not pass overhead once: in those years the Moon never climbs as far north as Mecca's latitude.

• In late 2026 the passes are on 5 October (04:50 UTC, 07:50 in Mecca, a waning Moon 32 per cent lit in the morning sky) and 25 December (23:18 UTC, 02:18 on 26 December in Mecca, 94 per cent lit, a day after the full moon).
• The next full moon straight over the Kaaba is on 13 November 2027 at 20:44 UTC, 23:44 in Mecca.
• The last pass before the gap is on 16 July 2031; the first after it is on 21 April 2037.

How Far North the Moon Reaches

To stand straight over a place, a body has to be at a declination, its distance north or south of the celestial equator, equal to the place's latitude. The Kaaba is at 21.4 degrees north. The Sun's declination swings between 23.4 degrees north and south every year, so it always crosses 21.4 north twice.

The Moon's swing changes. Its orbit is tilted 5.1 degrees to the Sun's path, and the tilt turns round once every 18.6 years. When the two tilts add up, at a major standstill, the Moon reaches 28.7 degrees north and south each month, as in 2024 and 2025. When they work against each other, at a minor standstill, it only reaches 18.6 degrees, as in 2034. From 2032 to 2036 the Moon's monthly reach stays below 21.4 degrees, so it cannot stand over Mecca. The cycle is explained in the 18.6-year cycle and the crescent.

Why Some Years Have Many Passes

Reaching the right declination is not enough: the Moon also has to be crossing the meridian of the Kaaba at that moment, which it does once every 24 hours and 50 minutes. In a year of large swings, the Moon's declination sweeps past 21.4 degrees quickly, usually between two meridian crossings, and only a few passes come close enough.

The passes pile up when the Moon's monthly reach is only just above 21.4 degrees. The Moon then turns round near Mecca's latitude and lingers there for days, so several meridian crossings in a row fall within half a degree. In 2030, when its reach is 23.5 degrees, there are 19 passes; in 2031, at 21.8 degrees, there are 13, including three nights running, 1, 2 and 3 February 2031. The same happens on the far side of the gap: 14 passes in 2037.

Why the Full Moon Only Comes Overhead in Winter

The full moon stands opposite the Sun. In the northern summer the Sun is far north, so the full moon is far south, and it cannot reach Mecca's zenith. In the northern winter the Sun is far south and the full moon far north. So every pass of a full or nearly full moon (over 97 per cent lit) over the Kaaba falls between October and February:

• 13 November 2027, 20:44 UTC
• 2 November 2028, 21:21 UTC
• 28 January, 20 November and 21 December 2029
• 11 November, 8 December and 10 December 2030

Each of these is near midnight in Mecca, as a full moon should be: the full moon stands highest around midnight. Then there is a long wait: the next full moon overhead after 2030 is on 20 January 2038.

A Moon that bright casts a clear shadow, so on these nights the shadow of an upright stick points away from Mecca across the whole night side of the Earth where the Moon is up, just as the Sun's shadow does by day. Moonlight shadows are soft and faint, though, and the Sun's two dates are far easier to use.

And Medina?

Medina is at 24.5 degrees north, three degrees farther north than Mecca. The Moon reaches that far only in years when its monthly reach is over 24.5 degrees: up to 2029, and again from 2039. From 2030 to 2038 the Moon cannot stand straight over Medina, a gap almost twice as long as Mecca's.

Frequently Asked Questions

Does this have any religious meaning?

No. It is a geometric event, like the Sun's passes, and it has no role in the Hijri calendar or in worship. It is shown here because it is a striking consequence of the Moon's cycles.

Can I see it?

From Mecca, yes, if the pass is at night or the Moon is bright enough to see by day. Look straight up. Outside Mecca you see the Moon wherever it is in your sky; the event only means that someone at the Kaaba sees it at the zenith.

Why "within half a degree"?

The Moon is about half a degree wide. A pass within half a degree means that someone at the Kaaba sees the Moon's disc at, or touching, the point straight above them. The counts change with a different limit. The years 2032 to 2036 stay empty for any limit up to three-quarters of a degree; with a limit of one degree a single pass appears in 2036, and 2033 to 2035 stay empty even with a limit of one and a half degrees.

See Also

• Finding the Qibla from the Sun's shadow
• The 18.6-year cycle and the crescent
• Supermoon, blue moon, micromoon
• The day the Moon does not rise: why moonrise skips a day every month

References

• Meridian crossings, altitudes and illumination are computed with the astronomy engine of this site, as seen from the ground at the Kaaba, with refraction. The numbers are reproduced by docs/research/sky-events.mjs and computed by packages/astronomy/src/skyEvents.ts in the Hilal Vision source.