Oracles of Heaven

Charlie Nelson
Managing Director, Foreseechange
July 2011

It is well known that the biggest influence on tides in the sea is the moon and that the second biggest influence is the sun.  Jupiter and Venus also have a very small influence and the other planets have negligible influence.

But less well known is that the cycles of the moon and the sun influence weather and climate (climate is what you expect, according to Mark Twain, but weather is what you get).

The moon has a cycle of 18.6 years, the lunar node cycle, which clearly impacts rainfall in Melbourne for example (see my articles on this subject at and

The sun has a complex cycle which averages 11 years (the sunspot cycle) and also other cycles such as the 22 year double sunspot (or Hale cycle) which are also correlated with the climate.  Furthermore, some research has found that the sunspot cycle is influenced by the orbits of Jupiter and Saturn!

No-one knows the chains of causality but if we could establish these then we could better predict the weather in both the short and long term.

What is more, there is a seasonal pattern to major earthquakes which is correlated with the earth's elliptical orbit around the sun (see my article at

Climate scientists in particular seem to have spurned this line of research. recently but much work has been done in this area by Robert Currie, a professor from the New York State University at Stonybrook and some others.

I happened across Currie’s work when reading “Weather’s greatest mysteries solved!” by Dr Randy Cerveny, President’s Professor in Geographical Sciences specializing in weather and climate at Arizona State University.  In a chapter titled “The mystery of the great American dust bowl” he discusses Currie’s work on cycles and notes that Currie believed that the tidal changes caused by the 18.6 year lunar node (or lunar declination) cycle created variations in regional climates around the world.

In one paper Currie identified an 18.6 year lunar cycle existing in 1,015 out of 1,219 weather records (R. G. Currie and D. P. O’Brien, “Deterministic Signals in USA Precipitation,” International Journal of Climatology 10 (1990): 795-818).

But he found that the relationship changed phase for a time (that is, expected dry periods became wet and vice versa) and then locked back into their original phasing.  However, he found that the phase changes varied in timing between locations (R. G. Currie and D. P. O’Brien, “Morphology of Bistable 180-Degree Phase Switches in 18.6-Year Induced Rainfall over the North-western United States of America,” International Journal of Climatology 9 (1989): 501-25).

Australia was not exempt from Currie’s analysis.  In Robert G. Currie and Robert G. Vines, “Evidence for luni-solar Mn and solar cycle Sc signals in Australian rainfall data,” International Journal of Climatology 16 (1996): 1243-1265, the first few sentences of the abstract are fascinating:

“Spectrum analysis of 308 yearly sampled Australian rainfall series yields evidence for two terms with periods 18.3 ± 1.8 and 10.5 ± 0.7 years in 270 and 182 instances, respectively.  The long-period term is statistically significant at a confidence level of 99.9 per cent.  They are identified as the 18.6 year luni-solar Mn and 10-11 year solar cycle Sc signals previously reported in other climate data such as American and South African rainfall, tree-rings world-wide, rainfall indices, air temperature world-wide, air pressure world-wide, sea level world-wide, river flow, American crop yields and livestock/poultry production, European fish catches and dates of wine harvest, varves, thunderstorm occurrence, Earth rotation, and volcanic eruptions.”

Ironically, that paper was published in Melbourne’s last wet year before the recently-broken long drought..

Currie’s work is short on describing the physical links, or chain of causality, between the lunar node cycle and rainfall.  He proposes no forecasting models, nor quantifies the impact of the cycle on rainfall, and does not take into account the influence of other factors (than the cycles of the moon and the sun) on rainfall.  By omitting other influential factors, the estimate of the impacts of these cycles will be unduly conservative – that is, the cycles will appear to be less statistically significant than they really are.

By not establishing the chain of causality and not developing forecasting models which may include other drivers, Currie’s conclusions have clearly not inspired the majority of climate scientists.

When Professor David Karoly of the University of Melbourne’s School of Earth Sciences kindly reviewed my earlier paper, he was clearly not convinced of the merit of further researching the impact of the lunar node cycle:  “There are other known low frequency variations, such as in the Pacific sea surface temperature and Indian ocean sea surface temperature, that can explain much of the low frequency rainfall variability. These relationships can be tested using physically-based models to support the statistical relationship.”

Cerveny concurs: in discussing why the relationships between rainfall and lunar and solar cycles aren’t being used for forecasting, he says “Scientists like cause and effect.  Rather than just say that variations in one aspect of nature match variations in another aspect, scientists in general like to explain through accepted physical processes why the association exists.  With the solar-lunar cycles and drought, we simply can’t say if the drought is the result of the combined solar-lunar cycles, or something else.”

Cerveny concludes that the ultimate cause of the periodic droughts in the American Midwest still remains elusive to climatologists.  He also says that “Are droughts responding to solar/lunar cycles or to changes in atmospheric circulation? Or, does the atmospheric circulation of the North Pacific respond to solar/lunar cycles and then in turn impact droughts?  At this time, we simply don’t know the answer.”

One wonders whether climatologists want to answer these questions.  And whether they have the curiosity to address the questions and the imagination to suggest and test hypotheses about the chain of causality.  Are they spending too much time looking at their computer screens and not enough time looking at the sky?

I have it on good authority that climate models under-estimate decadal and multi-decadal variability (see my article on global warming scenarios at so this neglected line of research is important both for forecasting and policy decisions.

The set of articles we will be writing on this subject will further investigate the impact of heavenly bodies on climate, earthquakes and other phenomena.  Contributions and suggestions are sought and will be considered for inclusion in our set, either as articles or as links.  Of particular interest are suggestions as to chains of causality.  Please contact me at