What exactly is a Suntag report?
An automated 16-page PDF analysis of a single location in Switzerland or Liechtenstein. Its core is a sunlight-and-shading study – how much sun the spot theoretically receives through the year and how the surrounding terrain blocks it by season. Around that it adds context layers for the same point: road and rail noise, public-transport access, mobile and fixed-broadband coverage, and long-term climate averages.
What does the sunshine analysis show?
For your location it shows the theoretical sunshine duration day by day across the whole year – how many hours of sun the spot would get each day under a clear sky, given only the shape of the surrounding terrain. You can see how sunlight changes with the seasons and when in the year the surrounding relief starts or stops blocking the sun.
How is it calculated?
From a digital terrain model of Switzerland – a 25-metre elevation grid published by swisstopo – combined with the sun's path through the sky across the whole year. For your point, Suntag traces the horizon in every direction, works out when the sun clears the surrounding hills and mountains, and sums the resulting sunlit time.
What does the report not take into account?
Trees and vegetation, buildings and other structures, current or planned construction, the weather, air quality, and any change to the surroundings after the report is generated. The terrain model deliberately excludes trees and buildings, so the analysis reflects the shape of the land, not what is built or grown on it. All figures are estimates and can differ from what you experience on site.
How accurate is it?
The terrain data and the sun-path calculation themselves are exact. How closely the report matches reality depends on what forms the horizon where the sun rises and sets for your location: where that horizon is made of hills and mountains, the report captures it well; where it is made of nearby buildings or trees, it does not – those are not in the terrain model. Open and rural locations therefore track reality more closely than dense urban ones.
Can I use it to decide whether to buy, rent or build somewhere?
It is a useful input, not a verdict. The report is general information – not a survey, an expert opinion, or architectural, legal or financial advice – and should not be the sole basis for a decision. Use it to compare locations, spot an obvious problem early, or bring informed questions to a viewing.
Can I use it to plan solar panels?
That is not what Suntag is for – dedicated PV tools do it better. But the horizon profile Suntag computes for a location is a useful input to those tools: it is exactly the shading information a solar-yield calculator needs.
