The heart of tech is coming to the heart of the Mediterranean. Join TNW in València this March 🇪🇸

This article was published on October 9, 2014

OpenSignal brings its crowdsourced weather reporting app to iPhone

OpenSignal brings its crowdsourced weather reporting app to iPhone
Paul Sawers
Story by

Paul Sawers

Paul Sawers was a reporter with The Next Web in various roles from May 2011 to November 2014. Follow Paul on Twitter: @psawers or check h Paul Sawers was a reporter with The Next Web in various roles from May 2011 to November 2014. Follow Paul on Twitter: @psawers or check him out on Google+.

In May last year, we brought you news on WeatherSignal, a new crowdsourced weather reporting tool. The Web and Android app came courtesy of the good folks at OpenSignal, the company that creates independent maps of mobile phone network coverage from mobile phone users.

As of today, WeatherSignal is available for iPhone users too, as the company looks to ramp up its weather data-collating efforts.

The story so far

Over on Android, WeatherSignal taps the native sensors on your device to garner more precise data in very localized areas.

At the time of writing last year, the Samsung Galaxy S4 was the most complete device in terms of built-in sensors, letting WeatherSignal automatically detect temperature readings, pressure, humidity, light intensity and magnetic flux. Other Android handsets can glean some of this data too, depending on how old the device is and what sensors it has.


The long-and-short of the process is that an algorithm has been developed to translate battery temperature into ambient temperature, while it taps the phone’s built-in light intensity meter to detect, well, light. And humidity? This is garnered via the hygrometer, while pressure is detected using the barometer.

That’s WeatherSignal in a nutshell, and there’s little question it’s an ambitious project. With the iPhone version, however, there are inherent restrictions on what it’s able to track.

Under pressure

On iPhone, WeatherSignal can only track air pressure which, as it happens, is the main metric the team at OpenSignal are interested in monitoring just now. Indeed, the company’s academic partner at the University of Washington is currently doing a lot of work around the role smartphone pressure readings may be able to play in enhancing weather forecasts.

It’s worth noting here that only the iPhone 6 and iPhone 6 Plus can really be used to obtain data, as previous models don’t have barometers. If you do have an earlier version, you can still download the app, but it’s for looking only.

This is probably one of the first, if not THE first, app to make scientific and academic use of iPhone barometer data.

While part of the notion relies on users to altruistically donate their (anonymized) data, there are actual benefits to using the app itself. For example, you can see what the (very) local temperature is like, and peruse other users’ data too via an interactive map. Yeah, it may appeal to geeks.


The chief reason for having a barometer on a smartphone is that it helps with location fixing – GPS alone can only determine so much about where you are.

Air pressure can reveal key information about altitude, and this data was always going to be an interesting by-product of introducing barometers to the latest iPhone models.


This is a milestone moment in many respects, as Apple has hitherto been closed to making sensor readings available to developers. It’s a notable step forward for a mobile operating system that claims a significant market share in many countries.

As we’ve seen with the main OpenSignal service, the London-based startup garners one hell of a lot of data via the millions of downloads it’s had on Android and iOS. And this data is valuable, as is the data it gleans from the standalone WeatherSignal app, which has been downloaded 270,000 times on Android, with 50,000 of these actively capturing data.

However, for crowdsourced weather reports to be truly effective, it needs many more devices around the world with WeatherSignal installed. “We just need more data, which we’re hoping can be achieved with the launch of WeatherSignal for iOS,” the company says.

You can grab WeatherSignal for iOS now.

➤ WeatherSignal [iOS] [Android]