Stand on Eastern Beach on the right morning and you will watch the Rock of Gibraltar make its own weather. A grey ribbon boils up off the 426 metre summit and pours westward over the town, smooth and unhurried, like a waterfall that never reaches the ground. Above you the sky is blue. Behind that ridge, ten minutes' walk away, the city centre has gone the colour of wet slate. That is the Levanter, and it is one of the few sights in Europe where you can sunbathe on a bright shore while a whole town sits under cloud a few hundred metres away. Read it correctly and it stops being weather you dodge and becomes a clock that tells you which side of the Rock to spend your day on. Most people meet the Levanter as a viral video, that great pouring ribbon, and assume it must be some local freak event. The science is tidy. The Levanter is an orographic banner cloud, which means it is shaped entirely by the land beneath it. When the easterly Levant wind blows in off the Mediterranean carrying plenty of moisture, the Rock stands square in its path and the air has nowhere to go but up. As it climbs the steep eastern face and reaches the cooler summit, the moisture condenses into cloud, which then trails away to the west like a banner from a flagpole. The same physics produces the famous plumes off the Matterhorn and off Everest. Gibraltar's version is simply the most accessible on earth, because here you can drink a coffee in town, ride a cable car or lie on a beach while it happens directly overhead. The cloud takes its name from the wind that builds it, the Levant, which Spanish speakers call the Levante. This is the single most useful thing a visitor can understand, so it earns its own section. The Levanter is lopsided. The wind arrives moist from the east, so the eastern face of the Rock and the thin strip of coast at its foot often stay bright, while the cloud forms at the summit and drapes itself down the western side, exactly where the city centre, the harbour and Grand Casemates Square sit. In practice, a morning when the centre of town feels close, humid and overcast can be a flat-out sunny morning at Eastern Beach or at the painted fishing houses of Catalan Bay on the far side. The eastern shore catches sun for much of the day while the town wears its cloud cap. Locals are so used to this that they barely glance up. A grey sky at your window does not mean a grey day for your trip; it usually means it is time to walk around to the other side. > When the town wears a cloud, the eastern beaches are usually basking. Knowing which way to walk is the whole trick. The Levanter is fussy about wind strength, and this is the detail that explains why it shows on some easterly days and stays away on others. The banner needs relatively light air to hold its shape. It tends to form and persist when winds sit below roughly 20 knots. Push much past 25 knots and the cloud is torn off the summit and shredded rather than draped elegantly down the lee side. Direction matters just as much. The classic moist Levanter rides in on a northeasterly to easterly flow. When the wind backs to a drier southeasterly, the air often lacks the moisture to build a proper banner, so you can have a brisk easterly day with a bare summit and no spectacle at all. The sweet spot, then, is a gentle to moderate moist easterly, never a gale. A true Levanter gale, more common in the shoulder seasons, brings wind and murk but a ragged, far less photogenic sky. The Levant wind can blow in any season, but the photogenic banner favours the warm half of the year. It is most frequent from July to October, with a noticeable secondary burst around March. Spring days can be especially clean, because the Mediterranean is still relatively cool then, which steadies the low level airflow and helps the cloud hold a crisp edge rather than smearing into haze. If your aim is to photograph the banner at its most theatrical, target late spring or high summer and watch the forecast for a moist easterly settling in. If you would rather have reliably clear blue skies over the whole territory, you want a westerly spell, when the opposing Poniente wind keeps the Rock bare. Our companion guide to the [best time to visit Gibraltar month by month](/blog/best-time-to-visit-gibraltar-month-by-month) breaks the seasons down in more detail. Glance at the summit and the flags each morning and you can usually call the day before breakfast. Use this quick read. | If you see this | What it usually means | Best move | | Cloud streaming west off the summit, light easterly | Classic settled Levanter | Head to an eastern beach or a southern viewpoint | | Grey lid over the town, bright to the east | West side trapped under cloud | Walk round to Catalan Bay or Eastern Beach | | Strong, gusty easterly, ragged or no banner | Wind above the cloud window | Save indoor sights; the upper Rock may be murky | | Dry southeasterly, clear summit | Too little moisture for a banner | Good clear day for the ca