Sunset & Sunrise Predictors: Reviews of Skyfire and SunsetWx

There are many variables that go into predicting if a sunrise or sunset will produce remarkable colors. It may seem like it’s futile for humans, but there are two sunset prediction apps that might be able to help us.

Some of these atmospheric factors that we need to take into consideration are:

• Cloud height & types
• Humidity
• Wind direction & speed
• Atmospheric particulates; pollution, smoke, ash, etc
• Topography

Wouldn’t it be nice to just check a map and know if it’s worth going out to shoot or not?  Especially on those super early, cold mornings when you wonder if it’s worth getting out of bed?

Reviewing predictions of SunsetWx and Skyfire apps

The two most notable sunrise & sunset predictor services available are Skyfire and SunsetWx. These were developed with photographers in mind, but guess what, you don’t need a camera to use them.

One is Skyfire, an add-on subscription service for The Photographer’s Ephemeris for iOS. The other is SunsetWx, a free website that you can save to your phone’s home screen.

You’ll see below that results are different when you compare sunset predictions between the two services.  The “ratings” system is very different between the two as well.

The main limitation of both of these: they’re only as accurate (at best) as weather forecasting usually is.

Intro to Skyfire

Skyfire was hatched when award-winning photographer Matthew Kuhns wanted a way to know where to go for good light.  Photographers will spend the majority of their time chasing light.  Matthew wanted to know where to go without wasting any time.

Skyfire uses satellite data from NOAA and the NWS to determine cloud cover.  Though those two services may differ, Skyfire will attempt to “average out” what the cloud cover might be.

Then it takes in many other variables, such as those listed at the top of this page, and runs them through algorithms.  These algorithms then spit out a sunrise and sunset forecast, using colored shading to tell you how photogenic the light and clouds will be.

The app is available exclusively as an add-on in The Photographer’s Ephemeris for iOS, an $8.99 essential app for photographers.  If you’re not familiar with it, TPE will tell you exactly where in the sky the sun & moon are throughout the day, where shadows will be, and more.

Features of Skyfire:

• Coverage of the continental United States, southern Canada, and Europe.
• Goal to maintain 80% accuracy; currently claims 87% accuracy rate.
• High-resolution model for very localized forecasts.
• “Basic” subscription level forecasts two days out and includes Golden Hour light forecasts.
• “Plus” subscription level forecasts four days out and sends push notifications when forecasts reach a set threshold for your favorite locations set in TPE.
• Forecast updated continuously throughout the day as NOAA & NWS data changes.
• Now available for Android in addition to iOS.

You can try Skyfire for free in a 30-day trial period.  The Basic annual plan is $29.99 ($2.49/mo) and Plus is $44.99 ($3.75/mo).  You can also get a three-month plan; Basic is $9.99 ($3.33/mo) and Premium for $14.99 ($5/mo).

Intro to SunsetWx – a FREE sunrise & sunset predictor

Maybe you’re not a photographer and don’t want to shell out the money for Skyfire. SunsetWx is a free sunset predictor that might work just as well for you.

SunsetWx.com works on much of the same principles but is web-based, and available worldwide.  It too was created by a photographer/meteorologist who wanted to create a “sunset predictor model”.  

The major variables taken into account for SunsetWx’s algorithm are cloud cover, moisture, and atmospheric pressure.

It doesn’t have the interactive controls that Skyfire has, thus you can’t “zoom in” as you can in Skyfire.

Also, note that the predictions given are independent of when the sun is actually setting – it will tell you how colorful the sunset would be if it were setting at the time of day you were looking at.  So you’ll need to use the controls and set your local sunrise or sunset time.

SunsetWx’s maps do have playback controls. They list every time zone in the U.S. for current map showing, so be sure you’re paying attention to your time zone.

SunsetWx will give a “vivid” rating to areas it deems to have the right mix of clouds, humidity, and pressure, and show these in warm oranges and reds. Dry clear air or low clouds with precipitation will get a “poor” rating with cool blues on the map.  “Average” in-between areas will be depicted by greens and yellows.

SunsetWx publishes prediction updates a few times per day, at a lower rate than Skyfire.

How the sunset predictor tests were conducted

I tried to control the tests as best I could.  This was my process:

• Check the forecast for a consistent number of hours prior to sunset.  Eight hours prior and four hours prior to sunset would be realistic times for my planning purposes.
• Get a good random spread of testing days regardless of the weather.
• Shoot a panorama from the same location, panning from the sunset azimuth in the west then through north.  I’ve drawn the coverage of the photo on the Skyfire screenshots.
• Make the photo at the exact sunset time.

Some days I was unable to get to my normal location, and/or not planning on testing that night but it happened anyway.  I’m including the results from those nights just so that you can get more data points.

I should also add that even though the data presented here only has a sample of ten days, I tried to check the sunset predictors every night even if I could not take any pictures.  I will discuss those nights in the end.

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Test Results

Interpreting the results below is fairly straightforward.  You’ll see Skyfire’s sunset prediction next to SunsetWx’s prediction, captured at the same time of day.  I’ve included updated predictions from Skyfire where I remembered to get them.

The area you’re looking at in the photos is drawn on the Skyfire screenshot.

April 18, 2017

Skyfire on the left, SunsetWx on the right, taken 3 hours before sunset.  Skyfire shows a 50%-60% chance of photogenic sunset.  SunsetWx rates sunset as “poor”.

April 19, 2017

Skyfire on the left, SunsetWx on the right, taken 8 hours before sunset.  Skyfire shows a 50%-60% chance of colorful sunset.  SunsetWx rates sunset as “average”.

Updated Skyfire captures 4 hours until sunset, then at sunset.

April 29, 2017

Skyfire taken at sunset while out playing with my new drone.  The sunset prediction is a 50%-60% chance of being photogenic.

May 1, 2017

Skyfire on the left, SunsetWx on the right, taken 6 hours before sunset.  Skyfire shows clear skies and a 0% chance of photogenic light. SunsetWx rates the sunset as “average” to “vivid”.

May 4, 2017

Skyfire on the left, SunsetWx on the right, taken 5 hours before sunset.  Skyfire shows a 50%-60% chance of colorful sunset.  SunsetWx rates the sunset prediction as “poor”.

Skyfire updated at sunset, showing an even lower chance of colorful sunset.

May 5, 2017

Skyfire on the left, SunsetWx on the right, taken at sunset.  Skyfire shows a 70%-90% chance of a colorful sunset.  SunsetWx rates the sunset as “average”.

The color during this sunset never quite “popped”.  Low clouds to the east blocked any further light after this point.

May 8, 2017

Skyfire on the left, SunsetWx on the right, taken 2.5 hours before sunset.  Skyfire shows a 60%-80% chance of a photogenic sunset.  SunsetWx rates the sunset as “average” to “vivid”.

Skyfire updated at sunset, lowering the chance of a photogenic sunset to 50%-60%.

May 9, 2017

Skyfire on the left, SunsetWx on the right, taken 5.5 hours before sunset.  Skyfire shows a 60% chance of photogenic sunset.  SunsetWx rates the sunset as “above average”.

May 14, 2017

Skyfire on the left, SunsetWx on the right, taken 2.5 hours before sunset.  Skyfire shows a 60%-70% chance of a colorful sunset.  SunsetWx rates the sunset as “poor”.

Skyfire updated at sunset, bumped up to 70%-80%.

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Conclusion: Skyfire vs. SunsetWx Predictions

As I mentioned earlier, I still tried to check this every night even though I could not take photos. I found those nights to be very inconsistent as far as results go.

Skyfire

I like playing around with Skyfire, especially in conjunction with TPE.  But is it worth the money for its sunset predictions?

From these studies I found it to be accurate, by my judgment, just over 50% of the time.

SunsetWx

The only thing I don’t like about SunsetWx is the scale of their map – the inability to zoom in.  Local terrain can influence sunset factors, especially where I live, and it’s hard to make these out in SunsetWx’s national map.

I also found SunsetWx to be accurate about 50% of the time, again by my own standards for how I rate a sunset.

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Overall thoughts on Skyfire vs. SunsetWx

I like SunsetWx’s rating methodology better than Skyfire.  They try to tell you what the “wow” factor will be.  Whereas Skyfire tells you “50% chance of sunset” much like someone will say “50% chance of rain”.  Okay, well, what kind of rain?  And how much?  This is why I prefer Vivid, Average, and Poor ratings more than percentages.

But then again I’m in love with The Photographer’s Ephemeris, and the added functionality of the sunset predictor tool in Skyfire is a big bonus.  Even though it’s correct just over half the time by my standards through these testing days.

Of course, the big problem with predicting a sunset is that “good” is completely subjective to the viewer.

I’ll continue to keep SunsetWx bookmarked on my phone and check it often.  I’ll also keep my subscription to Skyfire – it’s only the price of a Starbucks each month (sad how nowadays we relate prices to “how many Starbucks is that”).  However, I’ll probably really only trust Skyfire when the overlay is dark orange-red – that’s when they know it’ll be good.

Back when I was teaching the next generation of fighter pilots we’d always tell the students, “don’t get so caught up in the gadgetry that you forget to look out the big window.”

While a sunset predictor is a cool service, don’t get so caught up in it that you miss the big picture.