Thoughtful, detailed coverage of the Mac, iPhone, and iPad, plus the TidBITS Content Network for Apple consultants.

Dark Sky 5 Offers Hyperlocal Weather Forecasts for iOS

For the last year or so, one of the prime spots on my iPhone’s home screen has been occupied by Dark Sky, a weather app that provides some smarts beyond the usual current conditions and 7-day forecasts. Most weather apps rely on the same set of data from the National Weather Service or other weather providers and differentiate themselves largely on interface. For years, my favorite of these was WeatherBug, which I reviewed back in 2010 in “WeatherBug Elite 1.0” (4 March 2010). And in fact, WeatherBug retains a spot on my iPhone, right next to Dark Sky, for reasons I’ll explain shortly.

So why does Dark Sky stand out, and why it has become one of my most-used apps? On its initial screen, under the current conditions, it provides a forecast for the next hour that is usually on target. Not everyone will care about this, such as those in California or other places in the world where the weather doesn’t change much. Nor will people who spend little time outside. But here in upstate New York, and speaking as someone who exercises outside most days, I care deeply about the weather. And more to the point, I care deeply what the weather is going to do soon, right where I am.

Perhaps I want to go for a run, and it’s raining. I don’t mind getting wet, but I don’t like to start that way, so if my check of Dark Sky’s next-hour forecast tells me the rain will be passing in 10 minutes, I’ll wait. Or if I’m heading out for a long ElliptiGO ride on a nice summer day, I’ll check to make sure thunderstorms aren’t likely to appear seemingly out of nowhere within the hour (this happens!).

Similarly useful are Dark Sky’s precipitation alerts, which can be configured to alert you to rain that’s going to dampen your specific location. While volunteering at an aid station during the Cayuga Trails 50 mile ultramarathon, I was mocked by my friends when I reported Dark Sky’s notification that light rain would start in 8 minutes; they changed their tune after the drops started hitting our tent exactly on time. Later that day, when Tonya and I were browsing the craft booths at the Ithaca Festival, several vendors downloaded Dark Sky on the spot after seeing that it could tell them when to drop the sides of their tents. And on more than one occasion, we’ve packed up a picnic early due to a Dark Sky notification that hard rain would be starting in 15 minutes.

All this works because Dark Sky’s near-future forecasting has proven itself quite accurate. Exactly how Dark Sky achieves this accuracy, I don’t know, though I suspect it does what I previously did by feel in WeatherBug, where I used the animation of precipitation blobs in a radar map to estimate the likely destination and arrival time of the rain. More generally, Dark Sky relies on, a weather service from the same developers that’s also used by many other weather apps.

You can help out, too. In the recently released Dark Sky 5, if its conditions don’t agree with what’s actually going on outside, you can report your local weather back to to help improve its forecasts. Plus, if you’re using an iPhone 6 or iPad Air 2, both of which feature a pressure sensor, a switch in Dark Sky’s settings lets the app periodically send pressure data back to to boost forecast accuracy.

While Dark Sky’s next-hour forecasts are unusual among weather apps, its 7-day forecast screen (swipe left) is less innovative, at least on its face. For each day, an icon indicates the general weather for the day, and a temperature bar shows the predicted high and low. If rain is predicted, a percentage appears under the icon. The problem with this display is that you can’t tell from it if that 100 percent chance of rain for the day means it will rain all day, or that it’s guaranteed to rain sporadically throughout the day.

However, tapping any row in the list expands that day’s forecast to an hourly view, showing when Dark Sky thinks it will and will not rain, with tappable options to show the predicted likelihood of precipitation, temperature, wind speed and direction, humidity, and UV index. Personally, I care only about precipitation and temperature, but I could easily see sailors caring about winds, and those concerned about sun exposure checking out the UV index. Sunrise and sunset times appear at the bottom. This expanded hourly view is easily closed with another tap, or you can expand other days and see them all in one long scrollable list. It’s an inspired interface, and nicely less modal than many other apps.

How accurate is Dark Sky’s 7-day forecast? Honestly, although its broad strokes seem generally on target, it’s hard to evaluate just how accurate it is (I’d love to see a weather app that reported back on its accuracy). It often doesn’t quite agree with WeatherBug (which relies on its own independent weather service), but neither is shockingly good. Yes, it will probably rain next Tuesday, but will there really be an early morning rain followed by another band coming through in the mid afternoon? I wouldn’t plan on it, since no forecast can yet predict exactly how fast a weather front is moving more than a few days in advance, and in this part of the world, we have what Tonya and I call “pop-up thunderstorms” — precipitation blobs on the radar that appear out of nowhere rather than marching predictably across the country, west to east.

As you can tell, I really like radar maps. I credit that to growing up on a farm, where we needed to know when we’d have 2–3 days of nice weather to cut and dry hay for baling. My parents watched a morning TV showed called “A.M. Weather” every day in the summer (happily followed by reruns of “The Rocky & Bullwinkle Show”), and we listened to NOAA Weather Radio’s constantly updated reports on a special weather radio throughout the day. We’d start with that morning image in our heads and then mentally update it based on the radio reports. So having an app show what we were imagining is nearly indistinguishable from magic.

But that’s the main place where Dark Sky falls down — its radar map (swipe right) is weak, at least in comparison to WeatherBug. Yes, it shows a pin at the current location, and you can pinch to zoom, and there’s a triangular play button to animate the map’s contents. All just like WeatherBug. But Dark Sky tries to get fancy with its map, eschewing a flat map for a spherical representation of the globe, and showing the entire planet at first. It’s pretty, but annoying, since you likely don’t care about the weather anywhere else in the world, and having to zoom in on your current location each usage is annoying. Plus, the globe simulation has inertia, so it continues to move after you stop scrolling. The map itself is topographical, showing hills and valleys, along with bodies of water and major roads, but it doesn’t label the roads, or even towns and cities, making it harder to orient oneself. Perhaps because it’s trying to do so much graphically, it’s often slow to render as you zoom and pan. Sadly, the recent Dark Sky 5 release didn’t improve the map at all, even as the developers tweaked and polished nearly every other aspect of the interface.

The main thing Dark Sky’s map gets right is that you aren’t limited to the automatic animation. Instead, you can also manually scrub through the past 3 hours of radar activity, and even 1 hour of estimated future activity. That makes it all the easier to see where a thunderstorm is heading, and if the map was more usable in general, I’d rely on it regularly.

Along with the longstanding precipitation alerts, Dark Sky 5 introduces a daily summary alert that gives you a forecast for the day, and custom alerts that can notify you at a specific time if temperature, precipitation probability, snowfall, wind speed, UV index, or humidity will hit certain levels. Then there are severe weather alerts (we’ve had several flash flood alerts this summer), and to ensure that rainfall alerts don’t wake you up, there’s even an in-app Do Not Disturb option that can have different times than the overall iOS setting.

A recent addition to Dark Sky is an Apple Watch app, complete with a glance, and while it’s fine, I never find myself using it. The glance shows the current temperature and conditions, with the predicted high and low temperature and the time until sunset. That’s replicated on the first screen of the actual app, swiping left once provides the hourly forecast for the rest of the day, and swiping left again shows the 7-day forecast. There’s something about being able to see everything at once on the iPhone screen that makes me prefer it to the Apple Watch’s tiny display.

Lastly, although Dark Sky defaults to showing you conditions and forecasts for your current location, you can add locations manually by tapping the location display at the top of the screen and entering the city’s name (and state or province, if necessary). Bring up the location display again to see the forecast for where you’re heading on vacation, for instance; you can swipe left in that list to delete unused cities. If you regularly want to check multiple widely separated locations, you’ll probably want to use a different weather app that makes switching easier — Dark Sky is about hyperlocal forecasts, not checking the weather around the world.

Dark Sky 5 costs $3.99 from the App Store and works on the iPhone and iPad, although its iPad interface isn’t any different from the iPhone interface apart from being presented on a larger screen. Nevertheless, if you’re as weather-involved as I am, it’s worth the price.


Try productivity tools from Smile that will make your job easier!
PDFpen: PDF toolkit for busy pros on Mac, iPhone, and iPad.
TextExpander: Your shortcut to accurate writing on Mac, Windows,
and iOS. Free trials and friendly support. <>

Comments about Dark Sky 5 Offers Hyperlocal Weather Forecasts for iOS
(Comments are closed.)

Alan Forkosh  An apple icon for a TidBITS Supporter 2015-08-07 20:18
The microclimate notification feature is really great on the Apple Watch. A few days ago, the sky was generally cloudy but the thought of rain didn't even occur to me. As I was walking home, my watch tapped me and I saw the Dark Sky warning of light rain in 10 minutes. As I was about 15 minutes from home, I decided it would be wise not to dawdle. Sure enough, as I was about 1/4 mile from home, t did start to rain.

So enabling the Watch app is useful, if only for the better availability of the storm warnings.
Adam Engst  An apple icon for a TidBITS Staffer 2015-08-07 21:33
Is that related to the Apple Watch app, or just the notification from the iPhone app? I assumed it was just the latter. But yes, we had a similar experience while wandering around Ottawa at the end of June - the alert came just in time to help us avoid getting wet.
I use exactly these two app for exactly the reasons you do. I also find the Dark Sky UI better for reading hour by hour than WeatherBug. I like the WeatherBug daily forecast summaries that are written in words.

It would be ideal if WeatherBug had the same "in the future" weather maps of Dark Sky.

The Dark Sky UI on the iPad is, as you say, a duplicate of the one on the phone. It doesn't make as much sense on the iPad, though, to have the daily forecast line vertical. In the previous version, the forecast lines were horizontal, so you could see hourly forecasts for many days at once on one screen. I'd like to see that back again on the iPad.
Adam Engst  An apple icon for a TidBITS Staffer 2015-08-07 22:03
Yes! I should have mentioned the written-out forecasts, which often convey information that it can take me a while to interpret from Dark Sky's graphics. Sometimes it's just easier to read "Sunny and warm in the morning, with a 70% chance of thunderstorms in the afternoon." than it is to parse a graphic.
Norbert E Fuchs  An apple icon for a TidBITS Benefactor 2015-08-08 08:03
I checked for both "Dark Sky" and "WeatherBug Elite" in the App Store, only to learn that they are not available in the Swiss App Store, but only in the US App Store.

Does this mean that the weather forecasts are only for the US?
Adam Engst  An apple icon for a TidBITS Staffer 2015-08-08 09:14
Huh. I don't know why they wouldn't be available in the Swiss App Store. I can definitely get forecasts for other countries in both.
Tofino  2015-08-08 10:24
It's never been available in Canada either.
JohnB (SciFiOne)   2015-08-08 12:52
Does it display the stats from "yesterday?"

(My low energy heating and cooling requires adjustments depending on what is happening. It helps to know what happened yesterday or even today to get a handle on how to set things up for the next day. I currently use the website. That was recommended by a roofing contractor.)
Adam Engst  An apple icon for a TidBITS Staffer 2015-08-08 14:18
Nope. For that, I'd recommend checking out Seasonality.
JohnB (SciFiOne)   2015-08-09 01:47
Thanks. Looks like the "Seasonality Go" app might do the trick. BTW, I still use the Weatherbug app which I picked up after reading your 2010 review.
gastropod  2015-08-09 02:26
Forecast Advisor tracks forecast accuracy. Last year for Seattle, was pretty bad, but it's improved quite a bit for this year. It's still a pretty short track record though, so it's hard to tell what's luck and what's skill, especially since this year is record setting atypical.

Adam Engst  An apple icon for a TidBITS Staffer 2015-08-11 14:56
Thanks for the pointer! I'll have to try different places - I'll be curious if the accuracy varies notably by location.
Ted in NC  2015-08-10 18:53
Dark Sky is hilarious and gorgeous. My typical experience was the "rain in 15 min." notice, then, after 15-20 min. and no rain, checking again to see that the rain had been pushed out to like 45 min. Then, it wouldn't rain at all. It's joke, at least here in NC. The world globe and the looping global weather systems, esp. in the future, are fascinating, and the true beauty of this app, imho. Even though what's predicted often doesn't come to pass, Dark Sky really plugs a user into the past, present, and future of the weather systems in motion.
strumsky  2015-08-10 21:22
I do like Weather Bug, but still haven't using as primary source Wunderground (Weather Underground) for its accessible, ease-of-use radar, multiple reporting stations, data & crowd-sourcing. Haven't seen any discussion of it here. You're right, California doesn't change much but still, when it's about to, we outdoors types want to know, same as any other. Forecasting is not a "science" so much as an artful, intuitive system (a tool) relying on alert senses to confirm. I use tools, a toolbox of them; I don't rely on them to do my thinking.
Michael Whyte  2015-08-11 02:31
Dark Sky is not available from the Danish App Store. Does that mean it works only, or ,best, in North America?
Also, I am into food gardening, not running. I could use a app that keeps track of immediate past rainfall locally. Knowing the cumulative precipitation for my area over the past week helps plan additional watering.
Graham Samuel  2015-08-11 05:07
I just checked and Dark Sky is available in the UK app store. As an Englishman living mostly in France, I was curious as to whether it would forecast French weather. Bought it just now to find that the answer is'yes', perhaps not surprising since the official French weather service is fairly comprehensive and detailed and presumably provide the source of data. It knows exactly where I am (tiny village in the South West). I'll check its accuracy over the next couple of days.
Tommy Weir  2015-08-11 07:05
I'd also recommend Windyty.

Here's the end of Long Island in NY, not knowing the Engst precise whereabouts :-),41.212,-73.950,9

It has a series of overlays, cloud and rain, wind, temp etc. all on top of detailed radar maps.

The address in the addressbar reflects both position and overlay, making it useful for bookmarking, saving to home screen or having a folder of favourite locations.

It has detailed information by clicking or tapping directly on locations, and this gets quite nerdy, sailors and pilots have more information specific to their needs from coastal areas and airports respectively.

It's Norwegian and unknown to most US users. No app that I know of but the mobile interface is excellent.
I also use 'Storm'; its got the radar images I like (more like the weather underground classic page had), and alerts for key items like lightning (which as an amateur radio operator I'm keen on); Dark sky is good but I agree the radar in that is awful.
JohnB (SciFiOne)   2015-08-11 13:27
I don't know if this will work or not. A link to comic that seemed coincidentally appropriate.
Duane Williams  2015-08-12 13:25
I have found Dark Sky very useful for ultra-local rain forecasts. Everything else in the app is not very useful. I like the Weather Underground radar maps and I like their large number of personal weather station readings for temps, wind, humidity, etc.

At this moment the Dark Sky app is telling me that the temp is 92 ºF. My thermometer outside is reading 88 ºF. My thermometer is within 1-2 ºF of the nearest personal weather stations reporting to Weather Underground. I don't know where Dark Sky gets its temp readings, but it certainly isn't ultra-local.
Actually, according to the Dark Sky web site,it only works in:

"Dark Sky only works in the United States (including Hawaii, Alaska, and Puerto Rico) and the British Isles.."

but there is a place to add your email and country to be notified when Dark Sky will be available there. They say they are trying to expand to other countries. Depends on availability of radar maps and what is needed to be able to use them.
Adam Engst  An apple icon for a TidBITS Staffer 2015-09-07 11:30
Huh. I wonder if it's a case of not all features being available everywhere, since you can definitely get some data for some other cities - I just tried Sydney and Tokyo. Perhaps the it's the hyperlocal stuff they can't do elsewhere yet.
Adam Engst  An apple icon for a TidBITS Staffer 2016-09-22 11:02
There's now a Web version of Dark Sky, if you don't want to pull out your iPhone.