Business

App has rain on its radar

As the weather gets warmer and you spend more time outside, a new app can help you make sure you don’t get caught in a storm while you’re walking to an important meeting, golfing with clients or just hanging out with your friends.

Dark Sky is an app for the latest versions of the iPhone, iPad and iPod Touch that tells you how much rain to expect over the next hour based on your precise location.

The app takes radar information from the National Oceanic and Atmospheric Administration and uses a program and various algorithms to determine whether it will rain in the next hour and if so, when the precipitation will start, how long it will last and how heavy the rain will be.

The app displays a brief message about the weather now (e.g., “possible sprinkling”) and the weather for the next hour (e.g., “rain starting in 3 min, stopping 30 min later”). Above that is a line graph showing how strong any forecasted precipitation will be.

The app only predicts whether it will rain 30 to 60 minutes in the future (there are no other weather forecasts), but it’s usually accurate up to an hour in advance and can almost always give you a 15- to 20-minute warning about upcoming rain.

Dark Sky also uses the same techniques the app creators used to predict the rain to provide a radar display with a smoother animation than typically exists with Doppler images. You can access data and see what the storm will look like over the next hour.

The app currently costs $3.99 and works with the iPhone 4 and 4S, the iPad 2 and the new iPad and the fourth-generation iPod Touch.