How to Read the Aurora Forecast - Hotel Rangá


How to Read the Aurora Forecast

Unlock the secrets of the night sky with our guide about how to read the aurora forecast. Get a better idea about why these beautiful lights appear and how you can predict when they might make a showing. Keep reading to learn more.

Watching the northern lights dance in the sky is a bucket list experience. The shimmering green lights can be calm, stretching out in a long band high in the night sky. However, some nights they move and grow, swirling in stunning patterns. But how can we know if the northern lights will be calm or strong? And is there a way to know if they will appear? It all comes down to the aurora forecast. Keep reading to learn all our tips and tricks about how to read the aurora forecast.

Green northern lights reflected on a pond at Hotel Rangá in south Iceland.
The magical aurora borealis. Photo by Paige Deasley.

What are the northern lights?

Before we learn how to read the aurora forecast, we need to understand why the aurora exists in the first place. The aurora borealis, commonly referred to as the northern lights, is a natural phenomenon that creates stunning displays of colored light in the night sky.

These mesmerizing lights appear when charged particles emitted by the Sun interact with the Earth’s atmosphere and geomagnetic field. As these solar particles collide with oxygen and nitrogen atoms and molecules in the upper atmosphere, they produce radiant light.

Two onlookers admire the pink and green northern lights shimmering above Skógafoss.
An epic shot of northern lights dancing above Skógafoss. Photograph by Stefan Liebermann.

What are the best conditions to see the aurora?

In order to see the aurora, we first need dark skies. This is important to remember because Iceland does not always experience a true night sky. Icelandic summer nights are almost as bright as daytime–a phenomenon known as the midnight sun.

Dark skies can also be threatened by light pollution. Nowadays, big cities and even towns are filled with light. Though helpful for navigation, these lights make it especially difficult to see the stars and the aurora. Luckily, Hotel Rangá is located in the Icelandic countryside, far from any light pollution. What’s more, we even offer a special northern lights wake-up call service. Yes, we will call your room whenever the lights should appear – even in the middle of the night!

Besides darkness, we also need clear skies to see the northern lights. This means zero cloud cover–so rainy nights are a no go for the aurora. Sometimes the sky can look clear, but there can be very high clouds blocking the aurora. Keep reading to learn how to check cloud coverage.

Hotel Rangá offers a northern lights wake-up call service. Photograph by Stefan Liebermann.

What is the aurora forecast?

The aurora forecast is a prediction of the likelihood and intensity of the northern lights. This forecast is based on the weather conditions, solar activity, location, geomagnetic activity and time of day. After considering all of these factors, we can get a sense about whether the aurora might appear.

  • Weather conditions: Technology allows us to quite accurately assess the upcoming weather conditions in Iceland. We can look at the estimated wind and precipitation measurements, as well as current and predicted cloud cover over Iceland. Cloud cover is the key measurement when it comes to weather conditions. We have the most chances of seeing the aurora when there is zero cloud coverage.
  • Solar activity: Auroral activity is heavily dependent on solar activity. When the sun is more active and releases more charged particles, there is more chance that we will see an aurora.
  • Geomagnetic activity: When there is more geomagnetic activity, the aurora will be brighter and more visible further away from the magnetic poles. Geomagnetic activity is affected by solar activity including solar coronal holes. The level of geomagnetic activity is indicated by the planetary K index or Kp index. This index ranges from 0 to 9.
  • Location: It is only possible to see the aurora in locations close to the magnetic poles. If geomagnetic activity is particularly strong, it is possible to see the northern lights further away from the magnetic poles. Iceland is relatively close to the north pole, making it a great location to view the northern lights.
  • Time of day: It is easier to see the aurora during the darkest times of the night. This makes Iceland a prime place to see the aurora during the winter months. After the longest day of the year in late June, the days quickly get shorter and shorter. During December, there are only about 4 to 5 hours of daylight per day. This means there are 18 to 19 hours of darkness per day–plenty of time to see the aurora!
A green band of northern lights beside Hotel Rangá in south Iceland.
A green band of northern lights beside Hotel Rangá in south Iceland. Photo by Paige Deasley.

How accurate is the aurora forecast?

The aurora forecast can be quite accurate. Technology allows us to monitor the weather forecast and check solar and geomagnetic activity. But at the end of the day, the aurora forecast is only a prediction. We can never fully know when the northern lights will appear.

For example, the aurora forecast can indicate that it’s the perfect night to hunt for an aurora…only for the lights to be a total no show. And some nights, the aurora forecast doesn’t look promising, but the lights appear with striking intensity. Ultimately, it is the unpredictability of the aurora that makes it so magical–we never know for certain when the aurora will appear.

Because learning how to read the aurora forecast isn’t foolproof, it is always a good idea to visit Iceland for several days. In fact, Hotel Rangá has a special offer intended to help our guests have more chances to see the magical aurora. The Age of Aurora offer gives guests a 20% discount on a four-night stay at Hotel Rangá. Indulge in a luxury experience in Iceland while you wait for the aurora to appear.

Pink and green northern lights shimmer above the mountain Vestrahorn in south Iceland.
Pink and green northern lights dance about Vestrahorn. Photograph by Stefan Liebermann.

What websites should you use to check the aurora forecast?

We recommend two websites to that will help you learn how to read the aurora forecast. The first is–the official website of the Icelandic Meteorological Office. To navigate to the aurora forecast, you will first click on the ‘Weather’ tab. Then, look on the left side of the page–there is a link that says ‘Aurora forecasts.’

On this page, you will see a map of Iceland. On the top of the map, you can select various tabs to see the cloud coverage over Iceland. We recommend looking at the ‘Lower and mid-level clouds’ tab. Clouds are shown in the color green, while a white area on the map indicates clear skies.

After checking the cloud coverage, you can then look at the Aurora forecast on the right side of the page. You will see a range of numbers from 0 to 9 which derives from the Kp-index; 0 indicates the least amount of auroral activity while 9 indicates the most amount of auroral activity. Underneath the aurora activity, you can see the day’s sunrise and sunset as well as the time the moon rises and sets. another helpful website. This page is formatted similarly to On the left side of the page, you can see the cloud cover forecast. On the right side of the page, you can see the Kp-index ranging in numbers from 0 to 9. does include some extra readings which you will find at the bottom of the page. You can see readings for the ‘Solar Wind Speed’ and the ‘Interplanetary Magnetic Field’. There is also a real-time visual of the aurora forecast over the northern hemisphere from the NOAA Space Weather Prediction Center. There are also real-time images of coronal holes and sunspots. The prevalence of coronal holes and sunspots can indicate the potential for increased auroral activity.

Pink and green northern lights shine bright above Hotel Rangá luxury hotel in south Iceland.
Hotel Rangá northern lights hotel is the perfect spot to see this incredible natural phenomenon. Photograph by Stefan Liebermann.

Now that we have explained how to read the aurora forecast, it is time to go out and look for those dazzling green lights. Contact our reception staff today to book your stay at Hotel Rangá. Seeing the northern lights in Iceland is a once in a lifetime experience that you will always remember.

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