Is the flight to Switzerland turbulent?
Two things add bumps: the North Atlantic jet stream at cruise (clear-air turbulence, strongest in winter), and mountain-wave turbulence over the Alps on descent into Zurich and Geneva, where wind flowing over the peaks creates standing waves that jolt aircraft.
Why is the approach into Geneva and Zurich bumpy?
Both airports sit close to the Alps. When strong winds blow across the mountains, they form mountain waves and rotor turbulence downwind — the same effect that makes alpine approaches famously bumpy. It is usually brief and well understood by pilots, who adjust speed and altitude.
Why is there turbulence over the Atlantic?
The North Atlantic jet stream — a fast river of air at cruise altitude — creates wind shear at its edges that can jolt an aircraft without warning (clear-air turbulence, or CAT). It is strongest in winter and on the eastbound US→Europe leg, which rides the jet. Pilots change altitude to find smoother air, but CAT is invisible on radar, so it is the main reason to keep your belt on.
Where should I sit on a flight to Switzerland?
Over the wing, near the aircraft's center of gravity, gives the steadiest ride. Keep your seatbelt fastened even when the sign is off — clear-air turbulence over the Atlantic can appear suddenly. On overnight flights the smoothest air is usually found by belting over the blanket and staying buckled while you sleep.