In 2011, an iOS app called Dark Sky ignored the buffet of available meteorological data and asked a simple question: What do users want to know when they check the weather? By focusing on short-term, hyper-local answers to that question–whether you’ll need an umbrella in 10 minutes, for instance–they carved out a space for themselves in an already saturated market. Yesterday, Dark Sky received its first major redesign, including a re-imagined UI and dashboards that visualize the week ahead.
The flashiest new feature is an interactive world map of precipitation and temperature projected onto a 3-D globe. Users can spin the precipitation map to see incoming storms, or watch them unfurl via a smoothly interpolated animation of the previous and next few days. The temperature map, named “Project Quicksilver” by the developers, looks like a half-eaten gobstopper, rainbow gradients suffusing from the poles.
Tie-dye color scales are pretty, and they remind us of the red/green Dopplers we grew up watching on the morning news. But they’ve been off-limits in the graphics community for years once researchers realized that they just don’t work very well.
To understand why, ask someone to organize a batch of grayscale paint chips. They’ll come back with a set ordered by luminance, running from light gray to near black. That maps well to a relative scale. Ask them to do the same with red, green, yellow, and blue and they’ll flounder. Perceptually, the rainbow doesn’t follow an intuitive order. Full-spectrum color maps also transition poorly between hues, creating the false appearance of sharp transitions among the data. You can see those problems on Dark Sky’s temperature map, as the 40 degree difference between -20 and 20 (black to dark blue) isn’t nearly as drastic as the one between 40 and 80 degrees (green to white to orange).
Rainbow grouching aside, Project Quicksilver is a slick feat of forecasting. While the zoomed out default doesn’t necessarily invite local exploration, the app’s developers claim that every pixel on the map represents no more than 12.5 square miles. That’s a high enough resolution to capture almost 400 temperature zones in a region the size of the Los Angeles Metropolitan area. And the rest of the app presents a more straightforward forecast, never losing sight of its goal to only present actionable information. Current Dark Sky users can download the update for free, and new customers can purchase it for $3.99 in the iTunes App Store.