Somewhere on Earth there is a total solar eclipse every year and a half, on average: NASA says so, and so does Wikipedia, which puts it as 18 months. At any one spot, though, the wait is measured in centuries. The classic calculation, by Jean Meeus in 1982, gives an average of 375 years between two total eclipses at the same point; NASA, with a catalogue covering five millennia, gets 366, and a recent study refines it to 373 years, give or take seven. Spain now has two in a row, along different paths: last summer’s eclipse and the one on 2 August 2027.
Worldwide: every year and a half
There are solar eclipses every year. According to English Wikipedia, between two and five, and at most two of them can be total. NASA’s children’s site, Space Place, sums it up like this: a total eclipse happens roughly every year and a half somewhere on Earth. Why there isn’t one at every new moon, when the Moon goes round the Earth once a month, is explained with drawings in our learn section.
According to Wikipedia, a totality today cannot exceed 7 min 32 s. The 2027 one reaches 6 min 23 s in Egypt, the second-longest totality of the century; why it is called “the eclipse of the century” is in this article.
In one place: centuries
The Earth seeing a total eclipse every year and a half doesn’t mean you will see it. The Moon’s shadow traces a narrow path on the ground (the 2027 one is about 258 km wide at its widest, according to NASA), and each eclipse draws it somewhere different. How long it takes to come back to the same point has been calculated by several astronomers:
| Who | Average wait between two total eclipses at the same point |
|---|---|
| Russell and co-authors, in an astronomy textbook from 1926 | about 360 years |
| Jean Meeus, in a 1982 article in the Journal of the British Astronomical Association | 375 years |
| Ernie Wright, of NASA’s Scientific Visualization Studio, with Espenak and Meeus’s five-millennium catalogue | 366 years |
| Graham Jones and eight co-authors, in a recent article | 373 years, ± 7 |
NASA’s page with Ernie Wright’s figure compares it with Russell’s and Meeus’s and says it falls almost exactly between the two. English Wikipedia gives a range of 360 to 410 years, and Space Place goes with Meeus’s: a given place sees a total eclipse for only a few minutes, roughly every 375 years.
The article by Graham Jones and his co-authors returns to Meeus’s question with a new method. For annular eclipses they get an average of 226 years at a given point, and for any partial eclipse, 2.59 years. They also calculate that the most eclipses fall near the Arctic and Antarctic circles.
In Spain: the ones this site covers
In the history of eclipses in Spain (in Spanish) we cover those of 1842, 1860 and 1900 and the early-20th-century one that filled the streets. Then came the total eclipse of 1959, which in Spain was only seen in the Canary Islands, and the 2005 ring over the peninsula, which we look back on in the last eclipses in Spain.
Last summer’s eclipse, across the north, and the one on 2 August 2027, across the south, come one after the other. That doesn’t contradict the 375-year average, because the average is per point and the two paths don’t touch. Last summer totality fell on 3,952 of Spain’s 8,132 municipalities, spread over 31 provinces, and none of those provinces is among the 2027 ones (Cádiz, Málaga, Granada and Almería, plus Ceuta and Melilla), so no municipality gets it twice. The differences between the two are in how the 2027 eclipse differs from last summer’s, and the 105 municipalities with totality in 2027, in the full list.
Next comes an annular eclipse, on 26 January 2028, and in an annular eclipse there is no moment when you can look without glasses: we explain it in our learn section. We are not giving the date of the next total eclipse in Spain yet, because we haven’t checked it.
Sources: Eclipses — NASA Space Place (Spanish edition: a total eclipse every year and a half somewhere on Earth; a few minutes roughly every 375 years in a given place); Solar eclipse — Wikipedia (two to five solar eclipses a year and at most two total ones; a total eclipse every 18 months on average; 360 to 410 years in a given place; the maximum of 7 min 32 s); 5000 Years of Total Solar Eclipses — NASA Scientific Visualization Studio (366 years with Espenak and Meeus’s catalogue; 360 from Russell and co-authors in 1926; 375 from Jean Meeus in 1982); The Frequency of Solar Eclipses for a Given Place: A New Approach to a Classic Question — Graham Jones et al., arXiv (373 ± 7 years for a total eclipse, 226 ± 4 for an annular one, 2.59 years for a partial one, more eclipses near the polar circles); Path of the Total Solar Eclipse of 2027 Aug 02 — NASA, Fred Espenak (width of the path and maximum duration in 2027); municipalities and provinces with totality: IGN — eclipses.ign.es (in Spanish) and eclipseando data (skyfield + DE440s engine).
If you would like something to keep from the eclipse, the shop prints T-shirts, mugs and posters with the name of your town, the time of its maximum and its seconds of totality. See the merchandise →
Remember: never look at the Sun without proper eye protection (filters made to EN ISO 12312-2). The official reference for safe viewing in Spain is the IGN (in Spanish): eclipses.ign.es.