The Science Behind Lausanne's Sunsets

by Nicola Reinle

February 21, 2023

Maybe it's because our Insta story feeds have become a regular exhibition of incandescent evening skies, or because the sun’s end of work day coincides with many of us heading out of our respective offices for the night, but there’s something about nature’s canvas that had us wondering why there’s such glorious sunsets at this time of year in Lausanne. It turns out that we have the ideal ingredients thanks to science, the weather and Lausanne’s geolocation for the masterpiece we can feast our eyes on (almost) every evening.

The Science​

The color of the sky is related to how the eye perceives the wavelengths of color coming through the earth’s atmosphere. Sunlight contains all the visible wavelengths of the color spectrum (Roy G BIV, or however you remember the colors of the rainbow). As these individual color waves journey from the sun to our eyes they are ‘scattered’ by refracting off molecules in the air (for the name droppers, this is called ‘Reyleigh scattering’). It’s like the light is hitting millions of prisms and dispersing all the wavelengths separately. The highest energy, shortest light wavelengths (starting with violet and indigo) are scattered first, higher up in the atmosphere which is why in normal daylight, the air (mostly made up of oxygen and nitrogen molecules) scatter the violet, indigo, and blue colors so that the sky is perceived as blue by the human eye.

At sunset, the sun is lower down in the sky, so the light waves travel through more of the earth’s atmosphere than they did at noon (with more particles to cause the scattering), meaning the red, orange, and yellow hues are enhanced, whilst the blues and greens have already been filtered out, absorbed in the ozone and by other molecules.

The Weather​

Additionally, ’La bise’, the dry, crisp, glacial wind that tunnels through the pre-Alps and the Jura and slaps your exposed cheeks (rather than kisses, as the name would suggest), means less debris, humidity, and other aerosols in the air which would mute some of the colors observed at sunset. This results in those vibrant infernos of blazing oranges, reds, and pinks. You can thank the clean Swiss air for this too (Switzerland is in the top 20 countries of the world for clean air according to Air Quality Index.

Sunset Lausanne Cathedral

The Geolocation​

From Lausanne, overlooking the lake, the sloping angle of our city means we can find many unrestricted vantage points of the sky as the day passes and we watch the sun go from East to West and set over our neighbors in Geneva.

So, where can we enjoy front-row, unobstructed seats for this (literally) everyday spectacle?

  • Elevate your sunset experience and treat yourself to some high-end drinks and dining by booking an early table at the Sky Lounge.
  • Bring blankets and an apéro picnic to the Parc de l’Hermitage.
  • For a 360-degree staging of the twilight sky, stride up the Sauvabelin Tower.
  • To combine your panorama with rooftops, church towers, mountains, and the lake, find your viewpoint at the Esplanade de la Cathédrale.
  • Pair your sunset with a sauna (and maybe a cold dip) at the new public sauna spot Bains des Rives on the Bellerive Quaiside.