{"id":100423,"date":"2026-07-23T18:24:48","date_gmt":"2026-07-23T18:24:48","guid":{"rendered":"https:\/\/www.s1trail.com\/la-bora-il-vento\/"},"modified":"2026-10-17T16:49:52","modified_gmt":"2026-10-17T16:49:52","slug":"la-bora-il-vento","status":"publish","type":"page","link":"https:\/\/www.s1trail.com\/en\/la-bora-il-vento\/","title":{"rendered":"The bora, the wind that gives the race its name"},"content":{"rendered":"
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THE WIND<\/span><\/p>\n\n\n

The bora, the wind that gives the race its name<\/h1>\n\n\n

The katabatic wind that sculpts the Karst and gives its name to an entire event.<\/p>\n\n<\/div><\/div>\n\n\n\n

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The bora<\/strong> is the wind that gives the Corsa della Bora its name: it blows over the Karst and the Gulf of Trieste, mainly in winter, right on race weekend. This page explains what it is, when and how hard it blows, what the regulations say about running safely when it is blowing, and why it has become the name of a whole running event.<\/p>\n\n\n\n

What is the bora?<\/h2>\n\n\n\n

The bora is a wind that is katabatic<\/strong>: a cold, dense air mass of continental origin that builds up on the Karst plateau and, once the difference in pressure and density with the milder air below becomes great enough, plunges towards the Adriatic Sea, channelled through the passes of the Dinaric Alps. The main pass from which the bora that hits the Gulf of Trieste originates is Postumia\/Postojna (Slovenia), between the Nanos plateau and the Sne\u017enik\/Nevoso massif: a gap that acts as a funnel and sharply accelerates the airflow on its way down.<\/p>\n\n\n\n

The phenomenon is typical of the northern Adriatic, but it reaches its greatest intensity and fame in Trieste: the city is hemmed in between a relatively warm sea and a high, cold Karst hinterland, with a pass opening right onto the gulf. The name comes from Boreas<\/strong>, the north wind of Greek mythology. It is an intermittent wind, not a steady flow: it blows in gusts of varying strength (\u201crefoli\u201d in the Triestine dialect), carried by a relatively shallow layer of cold air, between 400 and 800 metres thick \u2014 which is why, in some places, the sky can stay clear above the bora while the wind at ground level is already very strong.<\/p>\n\n\n\n

When does it blow, and how hard?<\/h2>\n\n\n\n

The bora is a phenomenon that occurs mainly in winter<\/strong>, although it can also occur in other seasons. An Istrian proverb sums up its typical duration well: \u201cThree days it is born, three days it grows, three days it dies\u201d<\/em> \u2014 it starts, strengthens and blows itself out in cycles of about three days.<\/p>\n\n\n\n

In the ten years of weather statistics collected by the organisation for the editions of the Corsa della Bora (the page called Weather<\/a>), the race weekend \u2014 always in January \u2014 has historically been split between the bora (55% of editions)<\/strong> and the sirocco, the warm, humid wind from the south-east (45%): a figure that confirms how structurally exposed the period chosen for the race is to the phenomenon, without meaning that the bora is guaranteed every year.<\/p>\n\n\n\n

Over the years, weather stations in Trieste have recorded some of the strongest gusts in the Mediterranean, with readings that vary with the anemometer and how exposed it is: 171 km\/h<\/strong> in 1954 at the Thalassographic Institute \u2014 the gust that broke the measuring instrument, still cited as the best-known \u201chistorical\u201d record; 188 km\/h<\/strong> on 10 March 2010 (anemometer at the Nautical Institute); 182.88 km\/h<\/strong> on 11 February 2012 (ISMAR anemometer, Fratelli Bandiera pier). There is no single, authoritative \u201cofficial record\u201d: the figure depends on where and with what instrument it is taken, and the 1954 reading remains the most quoted because of its historical fame.<\/p>\n\n\n\n

The verified race-day figure is that of the edition 2021<\/strong> of the Corsa della Bora, run in the thick of a full-blown bora: 130 km\/h<\/strong> gusts, with air temperatures between 0\u00b0 and 6\u00b0 and a perceived temperature below zero \u2014 the only figure the organisation declares for one of its own editions, published on the page called Weather<\/a>.<\/p>\n\n\n\n

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