Where the sun goes in Arosa in winter
The 3,283 residents of Arosa (as of 2023) are spread across 334 inhabited hectares. 9% of them live in locations that get less than 2 hours of sun on 21 December, 41% in locations with less than 4 hours. On that day, the sunniest inhabited hectare gets 7.5 hours, the shadiest 0.0.
On the evening of 21 December, the sun disappears behind Älplihorn to the south-west (8° above the horizon, 7 km away). In the morning, the sun only appears from behind Schiesshorn to the south-east (10° above the horizon, 4 km away).
The paths show the position of the sun over the day; where a path disappears into the terrain, the residential location is in shadow. Chart at the population centre of Arosa, 1,873 m above sea level.
Hours of sunshine on the reference dates
- 21 December: sun on average from 10:10 to 14:37, 4.2 of 8.3 possible hours (astronomical sunrise 8:12, sunset 16:32).
- 21 March: sun on average from 7:43 to 17:31, 9.8 of 12.1 possible hours (astronomical sunrise 6:28, sunset 18:32).
- 21 June: sun on average from 6:38 to 19:39, 13.0 of 15.7 possible hours (astronomical sunrise 5:36, sunset 21:16).
Over the whole year, an average residential location in Arosa adds up to 3,387 possible hours of sunshine. With a clear horizon it would be 4,403; the terrain therefore costs around 1,016 hours, or 23%, per year. The difference between the sunniest and the shadiest residential location is 1,606 hours per year.
How the winter sun is distributed across the population
Hours of sunshine per neighbourhood
The most winter sun: Castiel (5.9 h), St. Peter (5.7 h), Peist (5.3 h). The least: Molinis (0.1 h), Innerarosa (3.4 h), Langwies (3.8 h).
| Neighbourhood / locality | 21 Dec sun from–to | 21 Dec hours | 21 June | Year | Shadow from |
|---|---|---|---|---|---|
| Arosa1,783 residents · 1,765 m | 10:05–14:23 | 4.2 h | 13.3 h | 3,377 h | Schaftällihorn |
| Peist147 residents · 1,333 m | 9:44–15:05 | 5.3 h | 12.4 h | 3,549 h | Tiejer Flua |
| St. Peter105 residents · 1,330 m | 9:43–15:23 | 5.7 h | 13.1 h | 3,721 h | Fuggs |
| Litzirüti102 residents · 1,449 m | 11:14–15:02 | 3.8 h | 11.2 h | 2,751 h | Furggahora |
| Castiel90 residents · 1,200 m | 9:44–15:38 | 5.9 h | 12.9 h | 3,753 h | Chuoregger |
| Innerarosa85 residents · 1,876 m | 11:27–14:53 | 3.4 h | 13.6 h | 3,437 h | Schaftällihorn |
| Langwies78 residents · 1,367 m | 10:52–14:39 | 3.8 h | 12.3 h | 3,186 h | Platzegga |
| Molinis74 residents · 1,074 m | 12:28–12:56 | 0.1 h | 12.9 h | 3,160 h | Chuoregger |
Averages of the inhabited hectares in the neighbourhood, weighted by number of residents. “Shadow from”: terrain behind which the sun disappears in the evening or appears in the morning on 21 December.
How it was calculated
- Terrain: swissALTIRegio (swisstopo, 10 m grid) within a 25 km radius; horizon in 72 directions, 3 m above ground. Required source attribution (editions from 2025): Bundesamt für Landestopografie swisstopo; Tarquini S., I. Isola, M. Favalli, A. Battistini, G. Dotta (2023). TINITALY, a digital elevation model of Italy with a 10 meters cell size (Version 1.1). Istituto Nazionale di Geofisica e Vulcanologia (INGV). https://doi.org/10.13127/tinitaly/1.1; DGM Österreich, geoland.at; DGM1, Bayerische Vermessungsverwaltung – www.geodaten.bayern.de; DGM 1 Baden-Württemberg: LGL, www.lgl-bw.de, dl-de/by-2-0”; RGEAlti, Institut National de l’information géographique et forestière, données originales tétéchargées sur https://geoservices.ign.fr/rgealti#telechargement5m, mise à jour du juillet 2023
- Residential locations: all hectares with residents (FSO STATPOP 2023), averages weighted by number of residents.
- Sun position to the minute for every day of the year 2026; times in CET/CEST.
- Not taken into account: neighbouring buildings, trees and cloud cover. Values are the astronomically possible hours of sunshine above the terrain horizon.
- Neighbourhood names and boundaries: swissNAMES3D (swisstopo). Municipal boundary: swissBOUNDARIES3D. Calculation as of: 2026-09-16.
Short answers
How many hours of sunshine does Arosa get in winter?
On 21 December, the sun shines for 4.2 hours at an average residential location in Arosa, on average from 10:10 to 14:37. Depending on the neighbourhood, the value lies between 0.0 and 7.5 hours. Cloud cover is not taken into account.
Which mountain blocks the sun in Arosa?
At the population centre of Arosa, the winter sun disappears in the evening behind Älplihorn to the south-west. In the morning, it appears from behind Schiesshorn to the south-east.
How much sun does my house in Arosa get?
This page only takes the terrain into account. For an individual address, neighbouring buildings and trees come on top, and in winter they often cast more shadow than the mountain. The SunPlot report calculates this for every address in Arosa using the official 3D building data, hour by hour over the whole year.