Forecasting With the Planets: What Is Astrometeorology?
The thermometer settled the matter this week. On 25 June, a weather station at Merryfield in Somerset reached 36.7°C, provisionally the hottest June day ever recorded in the UK. Closer to home for many readers, Cardiff hit 35.9°C, a June record for Wales, and Bute Park did not drop below 23.5°C overnight, the warmest June night the country has logged. A Red Extreme Heat warning hung over the south, and behind it forecasters were already watching for the thunderstorms that tend to break a spell like this. Every one of those numbers came from satellites, weather balloons and supercomputers running fluid dynamics on a scale the human mind cannot hold.
For most of recorded history, though, anyone wanting to know whether the coming weeks would scorch or soak looked somewhere else entirely. They looked up, and they read the planets.
A Sky Full of Weather Signs
Astrometeorology, sometimes called meteorological astrology, is the practice of forecasting the weather from the positions and movements of the Sun, Moon and planets. The word itself stitches together the Greek for star and for the things that hang high in the air, and the discipline is genuinely ancient. The method of reading weather from geocentric planetary alignments traces back to ancient Mesopotamia before being taken up and refined by Greek, Arabic and Renaissance thinkers, among them Ptolemy, Al-Kindi, Tycho Brahe and Johannes Kepler.
It is worth being clear from the outset, in the spirit that guides the work at Wilfred Hazelwood Astrology. The modern science of meteorology does not accept that Saturn or the Moon governs whether it rains in Swansea on a Tuesday. What follows is a tradition, a long and surprisingly rigorous one, rather than a rival to the Met Office. But it is a tradition that has shaped how people in these islands talked about heat and storm for the best part of two thousand years, and a heatwave like this one is the perfect moment to revisit it.
The Original Dog Days
Start with the phrase almost everyone reaches for when summer turns punishing: the dog days. It sounds like a comment on exhausted spaniels flat out on the kitchen tiles, but the origin is purely celestial. The dog in question is Sirius, the brightest star in the night sky and the chief star of Canis Major, the Greater Dog. Its Greek name, Seirios, means scorching.
The ancient Greeks noticed that the most blistering weeks of summer arrived when Sirius rose and set in step with the Sun. To them the arithmetic was obvious. Add the heat of the brightest star to the blaze of the Sun and you get the fiercest heat of the year. Homer, in the Iliad, calls Sirius an evil portent that brings fever down on suffering humanity. Virgil blamed it for drought and plague. The Romans named the stretch dies caniculares, the days of the dog star, and the English borrowed the idea wholesale by the 1500s.
There is a neat irony in invoking the dog days during a June heatwave. The traditional dog days fall a little later, roughly early July into mid August, and because of the slow wobble of the Earth's axis they have crept away from where the Greeks first marked them. The heat that has gripped Britain this week has arrived ahead of the star that was once blamed for it. The Greeks would have found that ominous in itself.
How the Tradition Actually Worked
Sirius gives the flavour, but serious astrometeorology was a good deal more systematic than star-blaming. Ptolemy laid out the framework in the second century in his Tetrabiblos, describing several approaches to weather prediction, most of which rested on casting and interpreting charts for key moments in the celestial calendar. Practitioners watched a handful of recurring factors:
- The angular relationships, or aspects, between the planets, the Sun and the Moon, especially conjunctions and oppositions
- The natures assigned to each body, with Saturn read as cold, Mars and the Sun as hot and dry, and the Moon as the great agitator of moisture
- The four seasonal turning points of the year, the solstices and equinoxes, treated as charts that set the tone for the months ahead
- The phase and position of the Moon, long held responsible for rain, tides and shifting winds
The logic was internally consistent even where it was wrong. A cold, dry Saturn drawing close to the Sun should, on this reading, pull temperatures down. Heat belonged to the Sun and to Mars, the red planet the ancients linked with fire. None of it would have predicted this week, but you can see the shape of a system in it.
Kepler, Goad and the Attempt to Make It Science
The most interesting chapter comes later, when astrometeorology brushed up against the birth of modern science. Johannes Kepler, the man who worked out that planets move in ellipses, took weather prediction seriously. He began keeping meteorological observations in 1593 to test his hunch that a conjunction of Saturn and the Sun brought cold, and from 1598 he was issuing calendars with astrological weather forecasts baked in.
Then came the Englishman who pushed the idea furthest. John Goad published Astro-Meteorologica in 1686, a vast work of more than five hundred pages drawn from over thirty years of daily weather records. Goad did something quietly radical for an astrologer. He gathered data, lots of it, and tried to correlate the geocentric angular separations between the planets, Sun and Moon against what the sky had actually done. He was attempting, in effect, to test astrology by observation rather than simply assert it.
The timing is poignant. Goad's great book appeared just one year before Isaac Newton's Principia, the work that would explain the heavens through gravitation and leave no obvious room for planetary influence on the weather. Goad had reached for the experimental method at the precise moment that method was about to render his subject obsolete.
What Survives, and What the Sky Still Offers
Astrometeorology did not vanish overnight. Societies devoted to it persisted in Britain into the middle of the nineteenth century, though mainstream science had long since stopped paying attention. Today the Met Office attributes weeks like this one not to Saturn but to a warming climate, noting that the kind of heat Britain has just endured is becoming more common as a direct result of human activity.
So why look back at all? Because the impulse behind astrometeorology is the same one that makes a heatwave feel like more than a number. People have always wanted the weather to mean something, to sit inside a larger pattern rather than fall on them at random. The Greeks read scorching Sirius into the summer and felt the season had a character, even a temperament. That search for meaning in the movements overhead is precisely the territory the Wilfred Hazelwood Clinic works in, not as a substitute for the forecast, but as a way of asking what the patterns of the sky might reflect in a life.
The supercomputers will tell you it is going to rain on Sunday, and they will almost certainly be right. The older tradition asks a different question, one no satellite can answer: what does it mean to live under a sky you believe is speaking to you. That question is a great deal older than the thermometer, and it has not gone away.
The Wilfred Hazelwood Clinic believes very strongly in the science of climate crisis, and wishes to deny the more fanciful claims of the conspiracy theorists.
