The most turbulent countries to fly over
The air at cruise height over Japan is bumpy 54% of the time, more than over any other country. Here is every country, from the bumpiest to the smoothest, with what causes it and when.
The 30 most turbulent countries
The share of the time the air at cruise height (about 30,000–34,000 ft) over each country is light-or-worse bumpy, averaged over every season and time of day.
- 1 Japan bumpiest in Dec · calmest in Aug 54%27% moderate
- 2 South Korea bumpiest in Feb · calmest in Aug 51%22% moderate
- 3 North Korea bumpiest in Apr · calmest in Aug 50%23% moderate
- 4 Chile bumpiest in Jun · calmest in Jan 40%19% moderate
- 5 New Zealand bumpiest in Sep · calmest in Jan 37%17% moderate
- 6 Georgia bumpiest in Feb · calmest in Aug 36%17% moderate
- 7 Azerbaijan bumpiest in Mar · calmest in Aug 36%17% moderate
- 8 Uruguay bumpiest in Sep · calmest in Mar 36%14% moderate
- 9 Bhutan bumpiest in Feb · calmest in Sep 34%16% moderate
- 10 Iceland bumpiest in Jan · calmest in Jun 34%17% moderate
- 11 Argentina bumpiest in Aug · calmest in Jan 34%13% moderate
- 12 China bumpiest in Mar · calmest in Aug 34%13% moderate
- 13 Ireland bumpiest in Nov · calmest in May 31%12% moderate
- 14 Switzerland bumpiest in Nov · calmest in May 30%13% moderate
- 15 Nepal bumpiest in Jan · calmest in Sep 30%11% moderate
- 16 United Kingdom bumpiest in Nov · calmest in May 29%11% moderate
- 17 United States bumpiest in Feb · calmest in Jul 29%11% moderate
- 18 Albania bumpiest in Jan · calmest in Jun 28%12% moderate
- 19 Mongolia bumpiest in Aug · calmest in Jan 28%10% moderate
- 20 Italy bumpiest in Nov · calmest in Jun 27%11% moderate
- 21 Kyrgyzstan bumpiest in Mar · calmest in Oct 27%9% moderate
- 22 Austria bumpiest in Jan · calmest in May 27%10% moderate
- 23 Jordan bumpiest in Feb · calmest in Jul 27%10% moderate
- 24 Norway bumpiest in Oct · calmest in May 26%10% moderate
- 25 Netherlands bumpiest in Nov · calmest in May 26%9% moderate
- 26 Belgium bumpiest in Nov · calmest in May 26%9% moderate
- 27 Spain bumpiest in Jan · calmest in Jul 25%10% moderate
- 28 Greece bumpiest in Jan · calmest in Jun 25%9% moderate
- 29 South Africa bumpiest in Jul · calmest in Feb 25%8% moderate
- 30 Iran bumpiest in Feb · calmest in Aug 25%9% moderate
Jet streams first, then mountains
The countries at the top sit under the world's strongest jet streams: the one over Japan and Korea in winter is the fastest on Earth, and the wind shear around a jet is where most turbulence at cruise height comes from. Countries under the southern jet, like Chile and New Zealand, follow.
Mountains add their own. Where strong wind crosses high ground it sets up waves that reach cruise height, which is why mountainous countries rank above flat ones at the same latitude.
The smoothest countries are in the tropics and subtropics away from the storm belts: no jet stream overhead, little high ground, and storms that come in seasons rather than every day.
The smoothest countries to fly over
- 1 Guyana bumpiest in Dec · calmest in Sep 2%0% moderate
- 2 Suriname bumpiest in Dec · calmest in Oct 2%0% moderate
- 3 Tanzania bumpiest in Jan · calmest in Apr 2%0% moderate
- 4 Cambodia bumpiest in Aug · calmest in Apr 3%0% moderate
- 5 Uganda bumpiest in Jan · calmest in May 3%0% moderate
- 6 Kenya bumpiest in Jan · calmest in May 3%0% moderate
- 7 Somalia bumpiest in Jul · calmest in Apr 3%0% moderate
- 8 Venezuela bumpiest in Dec · calmest in Sep 3%0% moderate
- 9 Congo - Kinshasa bumpiest in Jan · calmest in Apr 3%0% moderate
- 10 South Sudan bumpiest in Aug · calmest in May 3%0% moderate
Questions about turbulent countries
Which country has the most turbulence?
Japan. The air at cruise height over it is light-or-worse bumpy 54% of the time, averaged over every season and time of day in the report.
Which country has the least turbulence to fly over?
The smoothest countries are in the tropics and subtropics, away from the jet streams and the high mountains. The bottom 10 is above.
Is the ranking about the country's airlines or airports?
Neither: it is about the air over the country's land, at the height airliners cruise. A country's airports are ranked separately, by the routes that leave them.
Why are small countries missing?
The weather data comes in cells about 55 km across, and a country needs a dozen of them for a fair average. Singapore, Malta and other small countries are too small to rank on their own.
A ranking is the average. Your flight is one day.
FlyBud forecasts the turbulence along your actual route, at your actual time, and updates it as new weather comes in.