The Dog Days of Summer
The Dog Days of Summer were traditionally reckoned from the 3rd of July to the 11th of August, a forty-day period associated with Sirius, the Dog Star, the brightest star in the night sky. The name has nothing to do with dogs lying in the heat, though the image fits. It comes from Sirius, the bright star in the constellation Canis Major, the Great Dog, whose heliacal rising marked the hottest part of summer in the ancient Mediterranean world and came to be associated with the dangers and discomforts of high summer.
The Greeks called the star Seirios, meaning scorching, and believed its light added to the strength of the sun, tipping the season into something dangerous. Homer described it in the Iliad as a portent of suffering, bringing fever to wretched mortals. The Romans named the period the dies caniculares, the days of the Dog Star, and associated it with oppressive heat, disease, and uncertainty. It was said that wine turned sour, dogs went mad, and the natural world became less predictable.
The Dog Days in England
The 1552 edition of the Book of Common Prayer, a book that shaped the religious and social calendar of England for centuries, recorded the Dog Days as beginning on the 6th of July and ending on the 17th of August. Their inclusion shows how familiar the tradition had become. This was not a belief confined to folklore collections and country almanacs, but something considered important enough to be printed alongside the church calendar itself.
Brady's Clavis Calendaria, published in 1813, preserved the older beliefs in vivid language: "The seas boiled, wine turned sour, dogs grew mad, and all creatures became languid, causing to man burning fevers, hysterics, and phrensies." This was the received wisdom of the Dog Days, a period when the normal order of things seemed less certain and the world itself appeared slightly unsteady.
There is an English folk rhyme about them too, and like many folk rhymes it manages to cover both possibilities:
Dog Days bright and clear
Indicate a happy year.
But when accompanied by rain,
For better times, our hopes are vain.
Which tells you, essentially, that the Dog Days will either be fine or they will not, and either way it means something. This is the kind of forecast the hedgerow has always offered, less a prediction than a way of paying attention to what the weather is doing and giving it a name.
A Star, Not a Season
What surprises many people about the Dog Days is that they are astronomical rather than meteorological. The tradition is tied to a star, not the weather itself. In the ancient Mediterranean world, the heliacal rising of Sirius, its first appearance before dawn after a period hidden in the Sun's glare, became associated with the hottest and most oppressive part of summer.
The ancient Egyptians watched for Sirius more carefully than anyone. They knew the star as Sothis, and its appearance in the dawn sky heralded the annual flooding of the Nile. Those floods deposited the fertile silt on which Egyptian agriculture depended. For them, the rising of Sirius was not a warning but a promise, a sign that life-giving water was on its way.
The Greeks saw things differently. Sirius meant scorching, and the name itself reflects what they felt when they watched it return to the sky. They associated it with heat, drought, and illness, yet they also understood it as a seasonal marker, signalling that the most intense part of summer had arrived. The observation was accurate even if the explanation was not. Sirius has no influence on the Earth's weather, but people were watching the sky, noting the rhythm of the year, and giving it meaning. That habit of observation is one of humanity's oldest forms of knowledge.
The Unsteady, Crazy Dog
The Old Farmer's Almanac, first published in 1792, preserved a line about the Dog Days that captures their spirit better than any classical source:
"Make hay while the sun shines, for when old Sirius takes command of the weather, he is such an unsteady, crazy dog, there is no dependence upon him."
That is the Dog Days distilled into a single sentence. The weather cannot be trusted. The star is in charge and the star is unreliable. Make your hay while conditions hold, because once Sirius takes command you are at the mercy of forces beyond your planning.
The Old Farmer's Almanac is American rather than British, but it inherited the same European tradition found in the Book of Common Prayer and in Brady's Clavis Calendaria. The belief crossed the Atlantic with the settlers and continued in new landscapes and climates. The idea remained the same, a period when summer stood at its height and the first signs of change were already gathering beneath the surface.
St Swithin and the Forty Days
St Swithin's Day falls on the 15th of July, right in the middle of the traditional Dog Days, and carries its own famous weather belief. The saying goes that if it rains on St Swithin's Day, it will rain for forty days afterwards. If the day is fair, forty days of fine weather will follow.
The two traditions overlap strikingly. Both divide the year into a forty-day period, and both suggest that a single moment can shape what follows. Sirius in one case, a ninth-century bishop in the other. The number forty appears repeatedly in older traditions, forty days of rain, forty days of Lent, forty days of testing or waiting. It is long enough to matter and short enough to count.
Whether either tradition has any meteorological value is beside the point. What they encourage is attention. Mark a date, watch the sky, and see what happens next. That habit of observation sits at the heart of every traditional almanac.
The Hedgerow in the Dog Days
In the hedgerow, the Dog Days are the weeks when everything is at its fullest. Yarrow is flowering along field edges, a plant associated with wound healing for thousands of years, Achillea millefolium, named after Achilles of Greek legend. Meadowsweet fills the ditches with its cream-coloured flower heads and its sweet almond scent. Mugwort, the eldest of the herbs in the Nine Herbs Charm, stands tall along roadsides, silver-backed leaves catching the light whenever the wind turns them.
The hedgerow does not care about Sirius. It grows according to its own calendar, older than the names people have given to stars and seasons. Yet the Dog Days provide a useful frame, a reminder that the year has reached its hinge. The solstice has passed. The daylight is already shortening, though few people notice. The berries are beginning to form where the flowers once stood. The landscape is turning, almost imperceptibly, towards autumn.
The July Almanac zine explores the Dog Days, mugwort, yarrow, and the hedgerow at high summer, a collection of stories and observations that belong to this moment in the year and no other.
From the Shop
The July Almanac Box is open, containing two original signed prints, the 28-page illustrated zine, a golden-hour summer tea, a Common Blue Butterfly from the collectible wooden series, a pack of three shower cubes, and a printed moon phase calendar. Everything inside belongs to July.
The Botanical Hair Wash is also available, made with seven hedgerow plants including soapwort, marshmallow root, and rosemary.
Sirius is rising this morning, as it has every summer for longer than anyone has been counting. The brightest star in the sky, invisible in daylight, doing whatever it is that stars do while the hedgerow grows, the hay is made, and the weather follows its own course. Old Sirius, the unsteady, crazy dog. No dependence upon him at all.