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A simple weather app for data nerds.

A few days ago I was planting vegetables in my garden, but it’s been cold here lately and I wanted to know if we’d be hit by a frost during the upcoming week. Forecast informed me that it would get down to around 34° for the next few nights, dangerously close to freezing. If it remained above freezing, I could keep the new plants outside and simply cover them. If it dipped below, however, I’d be better off with them indoors for the night.

So the question was: how reliable was that 34°?

Forecast works by statistically aggregating a number of different weather models into a single forecast. Because I can peek under the hood, I was able to take a look at all the raw models and see how many dipped below freezing. I saw that none of them did, which gave me confidence that my plants would be okay.

Today we’re launching a new weather app that lets everyone “peek under the hood.” We’re calling it Forecast Lines:

http://forecast.io/lines

Forecast Lines shows you the forecast spread for each field (temperature, precipitation intensity, pressure, etc.), overlaid with our best guess of what will actually occur. It’s a simple idea, but a powerful one: at a glance, you can see what will happen over the course of the next week, and where we are most–and least–confident in our predictions.

And, it looks spectacular on your iPad, iPhone, or Android device. We hope you enjoy it!

By Adam Grossman