Crowdsourcing the Weather: Smartphone Batteries Reveal Temperature Information

Smartphones can be used in many different ways. And now, scientists are looking at a way to use the batteries in these devices to predict the weather. Weather experts and smartphone app developers have teamed up to develop a way to crowdsource temperature information from smartphone batteries.

Smartphone batteries have tiny thermometers to prevent the devices from dangerously overheating. Yet these selfsame batteries can also reveal information about the environment around them. If there was a way to harness this information, scientists could gain a better understanding of microclimates and could continuously update temperature readings as they change throughout the day.

In an attempt to turn this idea into a reality, the researchers crowdsourced hundreds of temperature readings from phones running the popular OpenSignal Android app. This app collects information voluntarily sent from users' phones to build accurate maps of cellphone coverage and Wi-Fi access points. They were able to estimate daily average temperatures for eight major cities around the world. These included London, Los Angeles, Paris, Mexico City, Moscow, Rome, San Paulo and Buenos Aires.

After collecting the data, the researchers needed to make some tweaks. A smartphone's environment can greatly affect its temperature. For example, a phone tucked into a pocket will be warmer than a cell phone kept out in the air. After calibration, though, the scientists were able to detect air temperatures within an average of 2.7 degrees of the actual value.

"The ultimate end is to be able to do things we've never been able to do before in meteorology and give those really short-term and localized predictions," said James Robinson, co-founder of the app developer OpenSignal, in a news release. "In London you can go from bright and sunny to cloudy in just a matter of minutes. We'd hope someone would be able to decide when to leave their office to get the best weather for their lunch break."

The findings could be extremely useful for helping with weather tracking in the future. More specifically, the crowdsourcing could potentially create weather maps that could vary block by block in cities. This, in turn, could tell users exactly what to expect when they step outside.

The findings are published in the journal Geophysical Research Letters.