Eight of the 10 most turbulent flight routes in Europe are to or from Swiss airports, the latest report from Turbli has revealed. A combination of short distances and mountains means flights to Switzerland are especially bumpy.

South America sports the world's bumpiest flight routes

To create the ranking, Turbli analysed 10.000 different flight routes to or from 55 of the world’s largest airports, to reveal which are the bumpiest. This was done by analysing turbulence data from the National Oceanic and Atmospheric Administration in the United States and the Met Office in the United Kingdom, which together record rates of turbulence around the world every six hours.  

This data is then combined into an annual average for each route, which is expressed via an eddy dissipation rate (edr). In short, an edr of between zero and 20 means a route has very light levels of turbulence, 20-40 has moderate turbulence, 40-60 has strong turbulence, 60-80 is considered severe while 80-100 means a route is known for having the most extreme turbulence on the planet. 

For 2024, the route between Mendoza in Argentina and Santiago de Chile was ranked as the most turbulent flight route on Earth. The hour-long flight achieved an edr of 24,6, meaning there is a chance of at least moderate turbulence year-round. The top three were found in the same region, with Cordoba, Argentina to Santiago and Mendoza to the Argentinian city of Salta rounding out the top three.

Flights to and from Switzerland some of the most turbulent in Europe

While South American routes dominated the global top 10, Turbli found that eight of the 10 most turbulent flight routes in Europe take off or land in Switzerland. The 299-kilometre route between Geneva and Nice took the top spot with an edr of 16,06, followed by Zurich to Nice and Zurich to Milan.

The main reason for Switzerland’s prominence in the ranking is the Alps. Turbli noted that mountain ranges increase turbulence in the air through so-called "mountain waves"; as air is pushed up and over the top of mountains, the resulting airflow produces powerful wind eddies and breaks which can lead to unpredictable and in some cases violent turbulence. This means that even during periods of good weather, flights over the Alps can still be very bumpy.

This is exacerbated by the fact that between Geneva and Nice, for example, the flight is not long enough for the plane to achieve an altitude where the worst of mountain-related turbulence can be avoided. 

Swiss airlines hope to better predict turbulence through technology

Interestingly, the Swiss government and airlines are at the forefront of predicting turbulence on flights. Speaking to Blick, SWISS spokesperson Silvia Exer-Kuhn explained that in 2019, SWISS and Edelweiss Air became the first European airlines to equip turbulence measurement devices, which transmit real-time data to authorities on the ground.

"In 2023, we introduced the "eWAS" weather app, with the support of the Federal Office of Civil Aviation, to project real-time turbulence measurements and forecasts directly into the cockpit," she added. In the future, the airline hopes the system will allow pilots to predict when turbulence will occur and take precautionary measures - such as switching on the fasten seatbelt sign - much earlier.

10 most turbulent flight routes in the world revealed

In all, here are the 10 most turbulent flight routes in the world in 2024, according to Turbli:

1. Mendoza (Argentina) - Santiago (Chile)
2. Cordoba (Argentina) - Santiago (Chile)
3. Mendoza (Argentina) - Salta (Argentina)
4. Mendoza (Argentina) - San Carlos de Bariloche (Argentina)
5. Kathmandu (Nepal) - Lhasa (Tibet, China)
6. Chengdu (China) - Lhasa (Tibet, China)
7. Santa Cruz (Bolivia) - Santigao (Chile)
8. Kathmandu (Nepal) - Paro (Bhutan)
9. Chengdu (China) - Xining (China)
10. San Carlos de Bariloche (Argentina) - Santiago (Chile)

Here are the most turbulent flight routes in Europe:

1. Nice (France) - Geneva (Switzerland)
2. Nice (France) - Zurich (Switzerland)
3. Milan (Italy) - Zurich (Switzerland)
4. Milan (Italy) - Lyon (France)
5. Nice (France)  - Basel (Switzerland)
6. Geneva (Switzerland) - Zurich (Switzerland)
7. Nice (France) - Lyon (France)
8. Geneva (Switzerland) - Venice (Italy)
9. Marseille (France) - Zurich (Switzerland)
10. Venice (Italy) - Zurich (Switzerland)

For more information about the study, and to see the top 10 for other regions, check out the Turbli website.