Caelum is an experimental mixed reality weather app that lets users search for the weather not the city.

Caelum is a mixed reality weather app that shows the weather around you. Instead of displaying the weather in your vicinity, this app acts as your weather guide if you want to go elsewhere. You can customize the range in which Caelum searches for your desired temperatures. It will then track your device's motion, showing you the current temperatures in the direction you're looking towards.


University project, fourth semester

Tools used

JavaScript, HTML, CSS, OpenWeatherMap API, Adobe Illustrator


Lukas Kenntner

Sampling pattern

Caelum is the result of a three-week short project in the course "Data Visualization". We were tasked to develop an app that uses weather data in an alternative way, different from typical weather apps. My team partner and I decided to create an app that works opposite from the default weather app.

Instead of searching for a city and getting weather information we wanted to search for weather and find cities. This service could be useful for people that want to hike on the weekend and don't know where to go. Also, photographers could use this to capture exactly the scene they want to shoot.

Motion Gestures

Since Caelum is a data visualization experiment, we wanted to explore different methods of interaction as well. In the app you can navigate between the cities (represented by cards) by making a short flipping-motion with your device.

Flipping forwards results in skipping to the next city (further away) while flipping backwards brings you to the city you checked out before (closer to you).

Motion gestures leveraging device's gyroscope
Color Scheme

The dominant part of the visualization is the use of color. Every step between 0°C and 29°C has its own color value to quickly give the user a sense of temperature.

The color schemes are divided in three ranges: 0°C - 9°C for the cold tones, 10°C - 19°C for the middle and 20°C - 29°C for the warm / hot colors. Together the colors combine into a seamless gradient.

Mixed Reality

The real world is represented in our application when navigating between cities. If the browser supports it, Caelum will keep track of the compass heading of your mobile device to present you with the data matching your direction of view. If this feature is not supported, the direction you're looking at when loading Caelum will be used as a reference point.


lines of code
cities per request
sampling rate
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