Frequently asked questions

Q1 - What is Suntag?

Suntag computes the theoretical number of hours of sunshine of every location in Switzerland.

Q2 - What is particular about Suntag?

Suntag takes into account the topography of the location as well as the trajectory of the sun (depending on the seasons) to compute how much sunshine may be received during the day.

Q3 - Does Suntag take into account large trees or tall buildings?

Suntag does not take into account the impact of vegetation (e.g. trees) and constructions (e.g. buildings).

Q4 - How long does a sunrise or a sunset last?

Technically speaking the sunrise or sunset is the period when part, but not all, of the sun is below the horizon. This takes about five minutes or so at our latitude. Suntag computes the trajectory of the center of the sun.

Q5 - Does Suntag take into account summer time?

Suntag does not take into account the one hour time shift in summer in the report, which explains why you will observe one hour difference between Suntag's computations and your observations on site during summer.

Q6 - Which data set does Suntag use to model the topography?

The topography of Switzerland is based on dataset (every 25m) provided by Swisstopo, which does not include trees or constructions (Licence #5701142104).

Q7 - Which data set does Suntag use to model the influence of the meteo?

The statistical data used to compute the influence of the meteo has been published by MeteoSuisse (Normwerte 1981-2010: Relative Sonnenscheindauer).

Q8 - I paid, but didn't get the email with the files.

Emails leave our server immediately, but it may take several minutes before they reach your mailbox. Please check your spam folder before contacting us. Keep in mind you can download the files as well.

Q9 - Can I pay through the post or simply make a bank transfer?

Unfortunately, the system only accepts payments by credit card.

Q10 - Do you offer unlimited one-year subscriptions for companies?

For the moment it is unfortunately only possible to obtain the analyses one by one.

Q11 - After payment I pressed the wrong button and something went wrong. How can I get my files now?

Please contact us with your payment details using the contact form.

Q12 - Suntag used to be free, why do we have to pay for the same service now?

Suntag used to be free because a generous sponsor financed its operating costs. After the loss of this sponsor, Suntag had to start asking users for a contribution towards the maintenance of the service.