Aurora forecasts predict the likelihood of seeing the northern lights, based on solar activity and atmospheric conditions. They give us an idea of when and where the aurora might be visible. A typical forecast includes details like the aurora strength (measured on the KP index) and cloud cover, both of which affect visibility. The excitement of seeing the northern lights lies in their fleeting, almost magical natureᅳa dance of green, pink, or purple light across the dark sky. However, their appearance depends on precise conditions, such as clear skies and high solar activity.
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What is the KP Index?
The KP (K-planetary) index ranks geomagnetic activity on a scale from 0 to 9, with higher numbers indicating stronger activity. This gives us an idea of how far south the northern lights might be visible. Far north, in places like Northern Norway, the aurora is overhead most nights, even with a low KP index of 1. Lower down, in Iceland, we usually need a KP index of 3 or above before the aurora can be seen.
When reading an aurora forecast, take the KP index with a degree of caution, as it’s not the most useful metric for northern lights hunting. The KP index is actually a 3 hour average of geomagnetic activity, taken from 13 stations around the world. So when you get a KP update, you’re looking at 3 hour old data. And as it’s averaged, high activity in one place may contribute to a higher KP which isn’t actually going to impact you, at your location, in that moment.
If you’re interested in learning more about this and the more scientific side of aurora forecasting, Vincent (The Aurora Guy) has written a great blog post about it.
The Aurora Oval
The auroral oval is a ring-shaped zone around the magnetic poles where the northern lights are most likely to appear. It’s created by charged particles from the Sun interacting with Earth’s atmosphere, and its position and size depend on solar activity.
The KP index becomes less useful at higher latitudes. If you’re sat under the aurora oval, but can’t see the lights and are wanting to maximise your chances, you need real-time data, specific to your location.
Solar Wind
Solar wind is a stream of charged particles that flows from the Sun and travels through space. Factors like the speed and density of the solar wind can help predict how intense the aurora might be, making it a key part of any forecast.
Forecast? We need a nowcast.
A lot of aurora forecast apps will simplify the forecast to KP and cloud cover. This can be useful to give a vague idea of whether or not the northern lights could be visible in your location, but you won’t find professional guides or scientists relying on apps like these.
NOAA
NOAA monitors and predicts space weather—everything from solar flares to geomagnetic storms that can affect Earth’s magnetic field. While other organisations study space weather, NOAA is the only one providing real-time forecasts and alerts that anyone can access.
Their Space Weather Prediction Center (SWPC) tracks solar activity like sunspots, coronal mass ejections (CMEs), and solar wind.
Aurora Forecast Apps
If like me, you’re not an astro physicist, this might sound a bit intimidating! Thankfully there are lots of user friendly apps we can use, which break down this data for us and use it to forecast our chances of seeing the aurora.
Space Weather Live
Space Weather Live is an essential app for aurora chasers, thanks to its real-time data sourced directly from NOAA. Unlike apps that rely solely on the KP index, it provides a more detailed and immediate picture of geomagnetic activity. One of its most useful features is the short-term forecast, giving us data on solar wind speed and density for the next hour.
Space Weather Live is in my opinion, the best aurora forecast app. There’s one graph in particular to pay particular attention to when out on an aurora chase, the real time solar wind data.
Real Time Solar Wind
Looking at the solar wind charts, you can see data for the next hour (it tells you how long it is estimated to take for the solar wind to propagate from their DSCOVR satellite to Earth). Essentially, the redder the plot goes, the better for aurora chasing.
If you can find a break in the clouds, or are out on a clear night, this data will let you know if there’s going to be activity soon.
Aurora Pro
Aurora Pro is the paid version of the app simply called Aurora. This is the app I’ve been using the longest and it’s great for beginners. It focuses on KP and cloud cover, but also has solar wind information available.
Aurora Pro has two features that I find especially useful: The user reported sightings map and, the ability to overlay the cloud cover map over the aurora oval. This isn’t an exact science, but it can show roughly if the cloud cover is over that whole part of the country, or very localised. And the visual cloud cover forecasts can help you drive somewhere to try and find a break in the clouds.
If you’re already in Iceland and can see there is geomagnetic activity, the user reported sightings come in really handy. Aurora Pro also has a page of web cams, which again can help decide on where to head next. For example, if you’re in your apartment and wondering if whether it’s worth heading out or not, but you see user reported sightings in the national park and aurora on a web cam nearby, it helps confirm the data you’re reading on the aurora forecasts.
Anecdotally, every time I’ve seen aurora in Iceland, Aurora Pro has correctly notified me that there would be aurora in the next 25 minutes or similar. I don’t pay attention to the longterm forecasts, but always ensure it’s setup to notify me and keep an eye on it, along with Space Weather Live. Whilst Aurora Pro does focus on the KP, at least visually to the user, I suspect it’s algorithm is pulling in other data to make it’s predictions.
Hello Aurora
Hello Aurora is another fantastic app I’ve seen recommended a lot in the aurora chasing community. Hello Aurora pulls in a lot of the data that Space Weather Live does, with a slick, easy to use interface. This app also has a cloud cover map and a nice community page where you can share what you’re seeing. As with all the apps, you can setup aurora alerts so you’re notified when it’s time to go outside.
I like that Hello Aurora shows you all the data, but offers explanations of what you’re seeing and what it means. It’s a brilliant app to use if you’d like to learn more about the science behind the aurora.
Dark Skies
The northern lights are not a winter phenomenon, in the sense that the space weather which causes them happens all year. But we associate them with winter, as on Earth we can only normally see them during the winter months. The poles experience polar night and midnight sun, periods of extended day or night. During the midnight sun, the lack of darkness makes seeing the aurora impossible, but during a big storm, it may be possible to see them elsewhere, as we did in UK this May.
Polar Night and Midnight Sun
Most of Iceland is not technically in the arctic, it sits just below the Arctic Circle line of latitude. As a result, Iceland does not experience true polar night or midnight sun, where the sun never rises/falls above/below the horizon. But that is a technicality, as Iceland does experience what most people would call midnight sun, given there is daylight for 24 hours for a few weeks during Summer. And during Winter, whilst the sun doesn’t disappear completely, they have reduced daylight. Just 4-5 hours during December.
This makes Iceland an ideal place to try and see the northern lights. During intense activity, you can see the aurora from Reykjavik. But you’d be better off heading somewhere dark, without light pollution, to maximise your chances of seeing the aurora.
Weather Forecasts
Unfortunately, you could have intense geomagnetic activity in space above you, but still have your chances ruined by weather here on Earth. Which is why in addition to the aurora forecast, you firstly need to look at the weather.
Weather on earth can be very localised, so the night is not necessarily a right-off if there’s cloud cover overhead.
To be successful in your aurora chase, you need a combination of clear skies and geomagnetic activity. Our longterm weather forecasts are more reliable than space weather, so I’d always recommend being aware of the clear skies forecast for the days ahead. As this is when you’ll have your best chance of seeing the northern lights in Iceland.
Weather in Iceland
Iceland is famous for it’s highly changeable weather. So do not be disheartened if you land in Iceland to rain/wind/snow … This is all part of the fun. I’ve been to Iceland countless times now and have never had a trip in any season where we didn’t experience a mixture of weather. There is a saying in Iceland: “If you don’t like the weather, wait”.
With that said, Iceland is a cloudy place. So finding those perfect clear skies will require some luck. During the winter months, it may be snowing, so thick cloud cover is common.
If there’s a break in the cloud, make the most of it. And be ready to go out at any point, as the weather is highly changeable.
The Best Iceland Weather Forecast
There’s no point firing up BBC Weather, putting Reykjavik in and hoping. Whilst your local weather app will be able to pull in some data, it won’t be as accurate as a local to Iceland forecast. Especially given how changeable the Icelandic weather can be.
The Icelandic Met Office is the best place to get your info from, not just for aurora chasing, but your whole trip. They will give any weather warnings too, so it’s always a good idea to consult this site before heading out in winter.
Planning Your Night
So now you hopefully better understand the aurora forecast and what to expect. It’s time to start your aurora chase.
Check the Weather Forecast
The weather will make or break your aurora chase, so always start here. If there’s a weather warning, or there’s a blizzard all night, get in the hot tub and try again the next night.
You may be blessed with clear skies all night, or there might be a break in the clouds at a set time. This is when you’ll want to focus your efforts.
Timing
Is it dark enough yet? Auroras can appear at anytime during the night, but the best hours are late evening to early morning. Be alert from 9pm onwards, but often things will get exciting a few hours after that.
Look at the Aurora Forecast
What is the KP? If it’s 3 or above, there has been geomagnetic activity within the past 3 hours in Iceland, which is a promising sign. Check the aurora oval, presuming the KP is 3, it’s likely to be above you now.
Go outside!
Own a smartphone? Use it to take photos of the sky, facing North. Even if you can’t see the aurora with the naked eye, you may pick up a green tinge on your phone.
The aurora will often start as a green tinge in the sky, which grows and develops, to the point where it can dance across the sky, as vivid in person as any film or photo you’ve seen on National Geographic.
Patience is needed, as this can take a while. I’ve learned to not rush out at the first sign of green, but any aurora visible means it’s time to start looking at Space Weather Live and preparing to head out.
This is also why I love staying in places with hot tubs in Iceland! You can watch and wait outside, without getting cold or bored. Just be ready to jump out and have your camera/outdoor gear ready to go.
Road conditions
If your real-time data is showing activity in the next hour and you can see evidence of the aurora (user reported sightings, aurora visible on web cams, a green tinge in the sky), then you might want to head somewhere darker, or to try and get that perfect shot.
Before going anywhere, ensure you’re confident to drive to the conditions (which in Iceland can often be challenging). Don’t take unnecessary risks and make sure you’re not distracted whilst driving.
Places like Thingvellir National Park can be a wonderful place to watch the aurora, free from light pollution.
What to Do If the Forecast Isn’t Promising
Aurora chasing can be frustrating at times, especially if you’re only in Iceland for a set amount of time. If the aurora forecast isn’t looking good, I always recommend booking a northern lights tour before you go home. That is presuming there’s not a full on weather warning, which means it’s totally futile. Tour guides not only know the best spots, but they’re experts in reading the aurora forecast. Not to mention, totally comfortable driving in Iceland and often in a much larger vehicle than your hire car. A good aurora guide will get you to the best spots and be able to maximise your chances of seeing the northern lights.
Book a Tour
I always book Iceland tours and day trips with Get Your Guide, have a look at the available tours and providers below (affiliate).
Good Luck!
The northern lights are my absolute favourite natural wonder. I hope that everyone who seeks them can see them and think Iceland is a truly wonderful place to try. I’ve seen the aurora in Iceland many times, but it never gets old. Whilst you’ll need good luck on your side, knowing how to read the aurora forecast can really help maximise your chances.
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