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Forecast – Worldwide Weather Forecasts From the Makers of Dark Sky (forecast.io)
151 points by spiralganglion on Mar 26, 2013 | hide | past | web | favorite | 45 comments

It's really nice to have another Weather API available. The only option I was considering prior to this was WeatherUndergrounds's API which is fairly simple to use. However, the pricing for Forecast's API is much better. Also, having a hyperlocal forecast for any lat/long is useful like DarkSky is.

Forecast's Pricing [1]

1,000 API requests per day is free. $1/10,000 API requests after that.

WeatherUnderground's Pricing [2]

You need to use their pricing calculator, and if you want historical weather, the price goes up a lot. $520/month for 5,000/API requests per day.

[1] https://developer.darkskyapp.com/terms_of_use.txt

[2] http://www.wunderground.com/weather/api/d/pricing.html

Not sure what sort of API you need (ie do you need raw data or map overlays)but this might be of interest: http://openweathermap.org

This might be of interest for you, there is a norwegian api for weather:


If you live in the Northwest, this resource, from the University of Washington, has revolutionized the exploitation of small weather windows for mountaineers in the Cascades. It's equally useful for choosing the right hour to ride your bike home, a day in advance.


Click on some of the WRF-GFS or NAM models. The 'km' denotes the grid size. Scroll down to a precip loop. Voila: tomorrow's weather, today.

At forecast.io, we use the GFS and NAM as two of our models (among others). More info on our data sources here: http://forecast.io/raw/

Clicking the map simulates the models for the day. You can also check the weather from any day in recorded weather history by clicking the time machine in the top right.

Dark Sky has been a shockingly useful app for preparing my motorcycle commute to/from work each day. But this... this blows it out of the water. Beautiful.

Same here, it's so useful to know, especially in FL ;)

Fantastic UI, I love the animations but wish I could drag to move around the globe. I love the rapid pace of weather API improvements. Good job :)

Looking at the raw data sources, I realized, that for my location (Hamburg, Germany), the data on humidity from gfs really seems to be an outlier sometimes, affecting the forecast.io-mean. Maybe, just maybe the some other statistical measure would compensate for this and make the forecast a little bit more accurate.

Median, or something like trimmed mean.

And, as the service is using the location of the user, why not show the weather in °Celsius, if the region, where the user resides measures in °Celsius (and Fahrenheit, where Fahrenheit is used). I really had to look hard to find the button, to switch.

But non the less, great service, design, that I like, not too much info at first glance, but the most important one, imho.

Loved the time machine feature.

Living in San Francisco for almost five years, I had to go back to my childhood in Massachusetts to test it. April Fool's day blizzard in Brockton, MA in 1997. Forecast.io shows heavy snow. I got like a week off from school. Works!

It lacks metric units (wind is in mi/s). I think that the contrast between ground and sea could be better; I had quite a hard time figuring out what region of the globe was actually displayed (I naturally first saw ground and sea reverted).

there is a C/F toggle at the upper right corner

Defaults to F though even though it knows where the user is located - for pretty much anywhere outside of the US I would think the default should be C.

[Mind you - it does remember your choice - so its not that bad]

Yes but it doesn't switch miles to km, only temperatures.

It doesn't look like this toggle exists on the mobile app.

In the web app, it's in the slide-right navigation. At the base, it looks like a speedometer toggle.

How does DarkSky accomplish this? Especially for a country like India.

I would like to start a weather forecasting service in my home country, India. Can someone here throw light on how I should go about it? Can I get any ready made softwares into which I can plug in parameters or do I need to understand many technical details and implement my own forecasting programs?

We just pull in a bunch of raw weather data from a bunch of sources. Most of them are free (although the ones that aren't tend to be silly expensive). Check out more here:


I guess I'll be the lone negative comment here... Personally, I find the mono iconography less useful than the ubiquitous blue/yellow/gray pictures. A cloud with two lines beneath means fog? Just not sure how that conveys it better.

Their summary is odd at times too. My next Monday shows: Icon: cloud with moon, Text: "Partly cloudy overnight.", Details: all clear

Love Dark Sky. Looks like they have executed this just as well.

I really wish Android had better support for web apps. iOS supports creating a shortcut identical to an app on the home screen, indistinguishable from a normal app. Android, on the other hand, only has home screen widgets. Ideally you could throw a bookmark in the app drawer too.

In mobile Firefox at least, long press on the address bar of the loaded site, and hit the "Add to home screen" menu item. It pops an app-like link onto your home screen.

The only giveaway when it's running is the address bar at the top.

  Android, on the other hand, only has home screen widgets
I don't put app icons on my home screen. That's what the app drawer is for. You can't put shortcuts to web pages in the app drawer.

Looks great. However, not being able to drag the globe around is annoying. From the UK, the global and regional maps are centred over Europe, but an overwhelming proportion of our weather comes from the Atlantic.

Getting smooth animations took an inhuman amount of effort... adding a rotating map would have been a little bit too much for launch. Hopefully we'll get to it in the near future.

Regarding the UK, you're right. I'll add a new view that's moved to the west.

I figured out it was a few PNG files with 3 channels each encoding various time points, and then a simple linear fade between images,

or was that more complex?

of course, computing & serving those time point samples might be slightly more complex:)

I made it so it just tells me when it's gonna rain. It's all I truly care about.


The temp should be specified in Fahrenheit or Celsius. The little toggle in the upper right hand corner is not enough.

haha damn, I started work this weekend on pretty much the same idea (and I even named it forecast)

This is great though, nice one :)

Anyone have it figured out what it is built in/on? Not sure I've ever seen a web app this responsive.

We just built it with a bunch of hand-coded HTML, CSS and JS. No fancy framework or anything.

Here's the builtwith report: http://builtwith.com/forecast.io

Cool guys. Very cool. What's the back end db?

The top layer of our backend is node.js running behind nginx. We use redis for storage, along with a bunch of flat files for certain things. Under that is a mostly ruby / mysql layer that manages a bunch of C programs for doing various number crunching tasks.

The mobile app is great on iOS 6. Negates the need for a native version IMO.

And should work on Firefox OS!

Looks great! One suggestion, though: since you're detecting the user's location anyway, couldn't you automatically use Fahrenheit only for the US and Celsius for all other countries?

Yeah yeah. We totally alienated a bunch of non-Americans by not having that in there. We'll add it!

This super-forecast is rather naive; for a given location and day-of-year it is the same for any future year.

I have this in my bookmark http://www.loopthy.com

Fahrenheit/Celcius toggle changes the visibility value but the unit stays the same (mi)

Oops! That'll be fixed and pushed this afternoon. One of the huge advantages of this being a mobile web app rather than a native app is we don't have to wait more than a week for bug fixes to be approved by Apple!

Also, another suggestion - perhaps kilopascals outside of US

GREAT app btw

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