The information on current weather events is supplemented by visual human observations. The atmospheric conditions around the observation site are described in detail.
Manual observation network
Visual observations provide a detailed description of the atmospheric conditions around the observation site. Meteorological observers make visual observations and take readings from measurement instruments between three and eight times per day every day of the year. This information is then transmitted to MeteoSwiss online. The reports are encrypted using internationally valid code and are made available worldwide.
Visual observations are made at around 30 locations in Switzerland. The following aspects are observed:
- Meteorological visibility
- Current weather: weather conditions at the time of the observation and during the past hour, e.g. moderate rain showers, snowfall, fog with formation of hoarfrost
- Past weather: the main weather phenomena during the past 3, 6 or 12 hours, e.g. thunderstorms, drizzle, drifting snow
- Ground conditions: e.g. powder snow covering the entire ground surface; frozen; damp
- Clouds: total cloud, level of cloud cover, type and sub-type of clouds in the area of sky visible from the observation site
- Instrument readings: e.g. fresh and total snow depth
Differences in the observation programmes of the individual locations are due to climatological and/or topographical factors. At elevated locations with a view into the valley, for example, clouds with their lowest part below the relevant observation post are also reported. This occurs at the Locarno/Monti, Jungfraujoch, Säntis and Zurich/Fluntern stations.