IL VENTO
The Bora, the wind that gives the race its name
The katabatic wind that sculpts the Karst and gives its name to an entire event.
La Bora It is the wind that gives the Corsa della Bora its name: it blows over the Karst and the Gulf of Trieste, especially in winter, precisely on the weekend when the race is held. This page explains what it is, when and how much it blows, what the regulations stipulate for running safely when it is present, and why it has become the name of an entire running event.
What is the Bora
The bora is a wind catabatica cold, dense air mass of continental origin that accumulates on the Karst Plateau and, when the difference in pressure and density with the milder air below becomes sufficient, descends towards the Adriatic Sea, channelled through the passes of the Dinaric Alps. The main pass from which the Bora originates, which strikes the Gulf of Trieste, is Postojna (Slovenia), between the Nanos Plateau and the Snežnik Massif: a gap that acts as a funnel and abruptly accelerates the descending airflow.
The phenomenon is typical of the Upper Adriatic, but it is in Trieste that it reaches its greatest intensity and notoriety: the city is squeezed between a relatively warm sea and a high, cold Karst hinterland, with a pass open directly onto the gulf. The name derives from North, the north wind of Greek mythology. It is an intermittent wind, not a constant flow: it blows in gusts (in the Trieste dialect “refoli”) of varying intensity, with a relatively thin layer of cold air, between 400 and 800 metres – which is why, in certain places, the sky can remain clear above the bora while on the ground the wind is already very strong.
When and how much does it blow
The bora is a phenomenon that is predominantly Winter, although it can manifest in other seasons. An Istrian proverb describes its typical duration well: “Three days it’s born, three days it grows, three days it cracks” — it is born, grows, and exhausts itself in cycles of about three days.
On the ten years of weather statistics collected by the organisation for the editions of the Corsa della Bora (page Weather), the race weekend — always in January — has historically been split between Bora (55% editions) and the sirocco, the warm, humid wind from the south-east (45%): this data confirms the extent to which the period chosen for the race is structurally exposed to this phenomenon, although this does not mean that the bora is guaranteed every year.
Over the years, weather stations in Trieste have recorded some of the strongest gusts in the Mediterranean, with readings varying depending on the anemometer and its location: 171 km/h in 1954 at the Thalassographic Institute — the gust that broke the measuring instrument, still cited as the best-known “historical” record; 188 km/h 10 March 2010 (anemometer at the Nautical Institute); 182.88 km/h 11 February 2012 (ISMAR anemometer, Fratelli Bandiera pier). There is no single, impartial ’official record“: the measurement depends on where and with what instrument it is recorded, and the 1954 figure remains the most frequently cited due to its historical significance.
The verified race result is that of the edition 2021 of the Corsa della Bora, held in the midst of a full-blown bora: 130 km/h gusts, with temperatures between 0° and 6° and perceived below zero — the only value that the organisation declares for its edition, published on the page Weather.
Running with the Bora: experience and safety in racing
The individual distance pages describe the bora as part of the experience, not as a hidden obstacle. The published text for the S1 TransKarst Ultra describes it like this: “Here, the Bora feels like a real part of the landscape: broader, more intense, and something you really want to talk about when you arrive.‘ On the section of the Mount Ermada ring road, common to several distances, the text of the S1 Half Trail It speaks of “ridge sections where the bora blows freely and the view stretches from the Julian Alps to Istria” — on clear bora days, the very same wind that makes the ride tougher also offers the best visibility.
security is not entrusted to the story, but to the Official regulations. The’Art. 7 Equipment requires each competitor to carry, for the entire duration of the race, the compulsory equipment listed on the page for their respective distance — with the explicit instruction not to choose the lightest possible clothing, but rather clothing that offers adequate protection in the mountains against adverse conditions (cold, wind, heavy rain and snow). For the longer and more exposed distances, the compulsory kit includes a thermal blanket, gloves, a hat, a windproof jacket, trousers and a long-sleeved top, and a head torch: this is not a mere formality, but the minimum equipment required to cross the most exposed sections of the Karst safely.
The’art. 24 Exceptional circumstances stipulates that the organisation reserves the right to modify routes, departure times, time limits, and the location of checkpoints and aid stations at any time; in the event of force majeure or conditions that may compromise participant safety, it may also postpone the start, adapt the itinerary, or cancel or interrupt a race already underway.
The bora in La Corsa della Bora
“S1” in the name of each distance (S1 Borin, S1 Half Trail, S1 TransKarst Ultra…) stands for Path 1, the CAI trail, much of which the race follows — that's how it's defined by the Official regulations. “Bora” is not merely a decorative addition: it is the wind which, as the website’s home page states, “sculpts the Karst, pushing you forward or bringing you to a halt, making every metre different from the last”. The motto accompanying the description of the Rilke Trail — featured in the text on all seven race pages — is “It's wonderful to be here”, taken from the *Duino Elegies* by Rainer Maria Rilke, the poet who stayed at Duino Castle on this very coastline, exposed to the bora: the very wind that makes the race tougher is part of what, according to the organisers, makes being there “wonderful”.
Two points on the course are objectively more exposed to the northerly wind, cross-referencing the published race descriptions with independent external sources. Val Rosandra/Dolina Glinščice, at km 13.2 (Bagnoli della Rosandra/Boljunec refreshment stop) — common section for S1 Trieste Ultra e S1 Bora Ultra is located Sella della Bora, the point in the province of Trieste where the wind reaches its maximum speeds: the two night races therefore cross, in the early hours of the race, one of the most exposed stretches in the entire territory. The second stretch is the’Ermada Mount Ring, path from the S1 Half Trail (The same sector is shared, without equally detailed description, by Borderless and TransKarst) — described in the published text as having a “ridge where the bora blows freely”.
La Corsa della Bora will reach its in 2027 12th editionEvery year the tracks are renovated, but the wind remains the only constant element from one edition to the next.
Cultural curiosities
Meteorologists distinguish between two types of bora. The Clear weather (anticyclonic) is associated with clear skies, very dry air, and exceptional visibility, caused by a well-structured anticyclone over central-eastern Europe. Dark bora (cyclonic) brings instead overcast skies, rain or snow, when cold air flows under moister, unstable air masses brought by a depression over the Adriatic. The difference is not in intensity but in surrounding conditions: the bora, as an air mass, has a thickness of a few hundred metres, so above it the sky can remain clear or be covered by sirocco clouds.
There is no specific “Bora scale” that is internationally recognised; wind intensity is measured using the standard Beaufort scale, the same as used for any wind. At a local level, the Civil Protection of Friuli Venezia Giulia issues strong wind advisories with colour-coded alert levels (yellow, orange, red) when forecasts indicate risk conditions.
In Trieste, there is a street named specifically after the wind: according to local historian Antonio Tribel (1884), the street got its name because when the Bora blows, it “hinders pedestrians more on this street than on any other” — the wind channels between the narrow walls of the street, increasing its intensity. The street is today part of the’Bora Itinerary from the TriesteMetro project. In the most exposed parts of the city, ropes or iron handles were once fixed to the walls of houses, which pedestrians could hold onto to continue their journey against the wind – a practical measure that became part of the city's imaginary of the bora. Trieste also hosts the Museum of the Bora — The Wind Warehouse, opened in 2004, it has grown over the years into a widespread museum with new spaces in Opicina.
In the dictionary of the Triestine dialect, “borin” specifically indicates a light bora, a brief gust – a curious semantic coincidence with the name of the shortest distance of the race, the S1 Borin (4 km), even though no consulted source explicitly states this origin for the race's name: it is noted as a curiosity, not a confirmed fact.
For the full, binding detail of mandatory material and safety clauses for each distance: Regulations Page. For the edition-by-edition weather history: Weather Page.