The summer that never came, and the night Frankenstein began

The fire in the salon of the Villa Diodati was lit in the middle of June, and nobody there thought it strange. Rain had fallen on something like a hundred and thirty days since April. Lake Geneva had risen until it flooded the streets of the city below, and in the mountains the previous winter's snow had refused to melt. Lord Byron had taken the villa for its view over the water. He got weather instead.

Five people sat in front of that fire, and by the standards of their own society all five were disgraced. Byron was twenty-eight and had left England in April under a cloud of debt, separation and rumour. Percy Bysshe Shelley was twenty-three, an atheist expelled from Oxford and still married to a wife he had abandoned. Mary Godwin was eighteen; her stepsister Claire Clairmont was eighteen too, and pregnant by Byron. The fifth was John William Polidori, twenty, Byron's travelling physician. Shut in by the rain they read ghost stories aloud, and then Byron proposed that each of them write one.

Two of those stories are still in print two centuries later. What nobody in the room could have known — what nobody alive knew, and nobody would establish for another hundred years — was that the summer they were sheltering from had been cancelled by a mountain on the other side of the world.

Why 1816 was the year without a summer

Fourteen months earlier and twelve thousand kilometres away, Mount Tambora on the island of Sumbawa in the Dutch East Indies had come apart. The first phase came on 5 April 1815; the climactic eruption started around seven in the evening on 10 April and threw a column forty-three kilometres into the air. It rated seven on the volcanic explosivity index, which makes it the largest eruption in recorded history, and the detonations carried 2,600 kilometres to Sumatra, where they were taken for the sound of guns.

The mountain lost about a third of its height. Ten or eleven thousand people died in the eruption itself, and between seventy and a hundred and twenty thousand across Sumbawa, Lombok and Bali in the starvation and disease that followed.

The part that reached Geneva was invisible. Sulphur dioxide carried into the stratosphere becomes a fine sulphate haze that circles the planet, scatters sunlight back into space and stays there for years. Global temperatures fell by between 0.4 and 0.7 °C. Averaged over a whole planet that is enormous, and in 1816 it was enough to give Europe the coldest summer in the entire instrumental record between 1766 and 2000. Contemporaries blamed sunspots.

What happened at the Villa Diodati in June 1816

Byron reached Lake Geneva in the last week of May and signed for the Villa Diodati at Cologny on 10 June, keeping it until 1 November: a square, arcaded house on a slope a couple of kilometres outside the city, with the water below it and the Jura across it. The Shelleys took a smaller house on the waterfront just underneath, the Maison Chapuis, and walked up the hill in the evenings.

Mary Godwin was the daughter of the philosopher William Godwin and the pioneering feminist Mary Wollstonecraft, who died eleven days after giving birth to her. She married Shelley that December, three weeks after his wife Harriet was found drowned in the Serpentine, and it is by that married name that everybody knows her. Polidori had been offered five hundred pounds by the publisher John Murray for an account of the tour, which is why a day-by-day record of that June exists at all.

The book they read aloud was Fantasmagoriana, a French translation of German ghost tales full of revenants and family curses. Polidori's diary for 15 June records what else the group had been arguing about: he and Shelley sat up talking about principles, and whether man was to be thought merely an instrument. On other evenings the talk turned to galvanism, and whether the spark of life might be a physical thing that could be supplied. Then Byron made his proposal. Polidori's entry for 17 June is four words long on the subject: the ghost stories, he wrote, were begun by all but him.

Nobody wrote down the night itself. Those two diary entries are the whole documentary record, and they bracket Byron's challenge to the evenings of 15 and 16 June 1816. Everything more precise than that is reconstruction.

How Mary Shelley came to write Frankenstein

The competition went badly for almost everyone in it. Byron wrote a fragment about a traveller named Augustus Darvell who dies in a Turkish graveyard and does not stay dead, then dropped it within days. Shelley began something founded on his own early life and gave that up too. Claire Clairmont wrote nothing. Polidori had a terrible idea about a skull-headed lady punished for peeping through a keyhole, and could not work out what to do with her.

Mary Godwin could think of nothing at all. She was asked every morning whether she had thought of a story, she wrote afterwards, and every morning she had to reply with a mortifying negative. Then, in the small hours, she had what she described as a waking dream.

I saw the pale student of unhallowed arts kneeling beside the thing he had put together. I saw the hideous phantasm of a man stretched out, and then, on the working of some powerful engine, show signs of life.

Mary Shelley, in her introduction to the 1831 edition of Frankenstein

She has often been doubted on that account. It is a very tidy origin story, written down fifteen years afterwards in an introduction to a new edition. In 2011 the astronomer Donald Olson took a team to Cologny, measured the ridgeline behind the villa, worked through contemporary weather records and calculated the moon's position for every night of that June. A bright gibbous moon cleared the hill and came through her window just before two in the morning on 16 June, exactly as she had described. The sky agrees with her.

The ghost story grew over the following year into a novel. Frankenstein; or, The Modern Prometheus was published anonymously in London on 1 January 1818, with a preface by Percy Shelley that led a good many early readers to assume he had written it. Mary Shelley was twenty. Her name did not go on a title page until 11 August 1823, with a second edition that followed Richard Brinsley Peake's stage version, Presumption; or, the Fate of Frankenstein, which ran thirty-seven times at the English Opera House that season. She went on 29 August and wrote afterwards: lo and behold, she found herself famous.

How Polidori's The Vampyre led to Dracula

Polidori did something quieter and almost as consequential. He picked up the fragment Byron had thrown away and finished it his own way, turning Darvell into Lord Ruthven: pale, magnetic, aristocratic, moving through London drawing rooms and destroying the people who trusted him. The Vampyre appeared in the New Monthly Magazine in April 1819, without his permission and under Byron's name. Both men protested. It was a sensation anyway.

Until then the vampire of European folklore had been a peasant revenant, a swollen corpse in a Balkan graveyard. Polidori made him a gentleman, and put him in society among people who could not tell what he was. Bram Stoker found that figure waiting for him seventy-eight years later.

What the year without a summer did to the rest of the world

Switzerland took it worse than almost anywhere in Europe. The failed harvests of 1816 and 1817 brought the last famine in Switzerland, and the last in continental Europe. Across the continent the death rate in 1817 ran more than fifty per cent above its already high level in the war year of 1815, and a typhus epidemic spreading from Ireland through Scotland, Switzerland and Italy killed more than sixty-five thousand people.

Bread prices brought violence wherever they rose. Armed labourers marched on the cathedral town of Ely behind flags reading Bread or Blood and fought a pitched battle with the militia, ten thousand people demonstrated at Manchester in March 1817, and rioters were hanged or transported by the score.

In North America the cold arrived as frost out of season. It snowed at Albany, New York, and at Dennysville, Maine, on 6 June; frost came five nights running at Cape May in New Jersey; lakes and rivers were still frozen in north-western Pennsylvania in July. Vermont lost between ten and fifteen thousand people to westward migration in two years.

The monsoon failed. Summer snow fell in Jiangxi and Anhui, the Yangtze valley flooded, and famine in Yunnan pushed farmers toward the one crop that still paid, which was opium. In Bengal a late monsoon followed by torrential rain is widely held to have made the conditions for the cholera strain that broke out in 1817 and became the first of the great global pandemics of the disease.

There were odder consequences. Horses were slaughtered or starved for want of oats across southern Germany, and on 12 June 1817 a civil servant in Mannheim called Karl Drais rode a two-wheeled steerable running machine seven kilometres to a coaching inn and back — the first bicycle, in a summer when a horse had become a luxury. The connection is often asserted and hard to prove. The coincidence of dates is exact.

What happened to the people at the Villa Diodati

Byron wrote the third canto of Childe Harold's Pilgrimage and The Prisoner of Chillon at the villa that summer, and in July a short poem called "Darkness", which begins: I had a dream, which was not all a dream. The bright sun was extinguished, and the stars did wander darkling in the eternal space. It reads now less like invention than like reportage.

The circle broke up in the autumn and most of it did not last long. Polidori, dismissed by Byron that September, died in London on 24 August 1821, aged twenty-five, from what was almost certainly self-administered prussic acid; the coroner recorded natural causes. Percy Shelley drowned off the Italian coast on 8 July 1822, a month short of thirty. Byron died of fever at Missolonghi on 19 April 1824, aged thirty-six. Allegra, Claire's daughter by him, died at Bagnacavallo in 1822, aged five.

Mary Shelley lived until 1851 and wrote six more novels, among them The Last Man, an account of a plague that empties the world. Claire Clairmont was the youngest person in the room and the one nobody was writing about — Mary's own account of that summer leaves her out, beginning "there were four of us" — and she outlived every one of them, dying in Florence in 1879 at the age of eighty.

Tambora is not finished. Small eruptions came inside the caldera around 1880, a gentle one in 1967 and a very small one in 2011, and in March 2026 Indonesia's volcanology directorate raised the alert level to 2, deep earthquakes beneath the mountain suggesting magma on the move again. The house at Cologny still stands, divided into apartments.