Free tool
Type an address and see when the sun really arrives: real buildings, real shadows, floor by floor, from the longest to the shortest day. Free, no sign-up.
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Direct sun between 2 pm and 6 pm, computed on the 3rd floor with official building heights.
For every moment we compute the sun’s altitude and direction to the minute for Vienna (48.2° north), in Vienna local time including daylight saving. At the summer solstice the sun climbs to about 65 degrees, at the winter solstice it stays below 19: which is why 21 December is the honest stress test for any flat.
For Vienna we use the City of Vienna’s official building model: every building body with its surveyed height. From it we build a full-circle horizon for your address: which neighbouring house blocks the sun from which direction, exactly when, and from which floor you see over it. Outside Vienna, OpenStreetMap data takes over.
Trees, terrain (such as slopes at the city edge), window sizes and planned buildings are not included. The sun check shows the sunlight a location offers: whether it reaches your rooms also depends on layout and windows.
A real point on Neubaugasse (1070 Vienna): at ground level it gets only about half an hour of direct sun on 21 December, on the 6th floor almost five hours, more than half the winter day. In Gründerzeit districts the floor often matters more than the orientation. Check your address in the tool above: it takes seconds.
Computed with this tool · as of July 2026
A south balcony gets the midday sun and is the only one that sees meaningful sun in winter: the low winter sun comes almost exclusively from the south. A west balcony delivers evening sun, often the more valuable one for commuters, but heats up most in summer. East sides get morning sun, north sides practically no direct sun.
Gründerzeit quarters are dense: streets of 15 to 20 metres meet eaves heights around 21 metres. Street-side ground floors often get no direct winter sun at all. Upper floors gain disproportionately: the floor often decides more than the orientation.
New quarters are more loosely built, but they grow: today’s open view can be built up in five years. The sun check does not know planned buildings, so for new areas look at the surrounding plots, and when in doubt run the winter test with the slider.
The sun position is computed astronomically to the minute, in Vienna local time including daylight saving. Buildings in Vienna come from the city’s official building model with surveyed heights per building body; outside Vienna from OpenStreetMap. Trees, terrain and planned buildings are not included: the result is a very good orientation, not a survey.
A continuous period during which a spot gets direct sun. The sun check lists all sun windows of a day to the minute, including the times when a neighbouring house takes the sun, and shows which building it is.
There is no fixed norm for flats. As a rule of thumb, winter decides: a location that gets one to two hours of direct sun on 21 December feels bright all year. Street-side ground floors in perimeter blocks are often at zero in winter. So always check the shortest day, not June.
For brightness across the year: south, because only there the low winter sun arrives. For evening sun after work: west, at the price of summer heat. The facade mode in the tool shows both for your exact address.
Because the street is narrower than the houses are tall: with eaves around 21 metres and streets of 15 to 20 metres, the winter sun (below 19 degrees) never reaches the bottom. That is why sun hours rise clearly with every floor.
Yes. Outside the official Vienna coverage we use buildings from OpenStreetMap: some heights there are estimated, and the source line under the tool says so honestly.
Nothing. The sun check is part of wohnwahn, a private, independent and free project for honest flat hunting in Vienna. No sign-up, no ads: and if you like, the page shows you flats with afternoon sun right away.
wohnwahn shows the data no portal shows for every flat: location, climate, real travel times, and the sun included.