Aurora Forecast Guide

What causes the Northern Lights

The Northern Lights, also called Aurora Borealis, happen when solar wind particles hit atoms in Earth's magnetosphere. This pushes electrons in those atoms to a higher energy level. When the electrons drop back down, they release light. That light show is the aurora.

Auroras are active all year. But you can only see them when the sky is dark enough, so winter is the best season to travel.

The best places to see them sit near the Arctic circle, above 60° latitude. This includes Norway, Sweden, Finland, Iceland, Canada, Russia and Alaska.

A beginner's guide to chasing the Northern Lights

Seeing the Aurora Borealis is a bucket-list experience, but it requires being in the right place at the right time. To maximize your chances, you need four key ingredients:

• Clear skies: Clouds will block your view.
• Strong solar activity: The sun needs to be active enough to fuel the lights.
• Darkness: You need to get away from bright city light pollution.
• Good timing: To give yourself the best shot, travel to the Aurora Zone. This includes the northern parts of Norway, Sweden, Finland, Iceland, Canada, and Alaska.

Hello Aurora keeps aurora lover ahead with real-time data, personalized alerts, and global sightings. Never miss the aurora again. Download Hello Aurora today

How to read the aurora forecast

Chasing the lights should not feel like guesswork. Hello Aurora pulls live space weather data and turns it into simple numbers you can act on. Here are the metrics that matter most.

Aurora Strength

Aurora Strength is a real-time measurement used to predict how active, bright, and visible the Northern Lights are at any given moment. Think of this as the main "go or no-go" signal. It measures real-time changes in Earth’s magnetic field caused by solar activity.

The Aurora Borealis are caused by streams of charged particles from the sun smashing into Earth’s magnetic field. When this happens, it causes the magnetic field to vibrate, bend, and fluctuate. Magnetometers detect these fluctuations and record them in a unit called nanoteslas (nT). The bigger the fluctuation in nanoteslas, the more intense the aurora display will be.

• When it drops sharply (around -150 nT): A "substorm" is happening. The lights are likely actively dancing right now. The lower this number goes, the wilder and brighter the show will be.
• When it spikes up (around +150 nT): The aurora is "charging up." Get your camera ready, because a display is often just minutes away.
• When it hovers near zero (around 5 nT): The skies are temporarily quiet. Time to grab a warm drink and wait.

Real-Time Solar Wind (RTSW)

Real-Time Solar Wind, or RTSW, is live solar wind data published by NOAA's Space Weather Prediction Center from SOLAR-1, its satellite at the L1 point about 1 million miles from Earth. SOLAR-1 replaced the older DSCOVR satellite in mid-2026 and gives forecasters 15 to 60 minutes of lead time before the solar wind reaches Earth. Full technical details are on NOAA's site.

This lead time matters for aurora hunters, and it is why we build our forecast on official RTSW data. Hello Aurora reads this feed directly from NOAA, so your forecast updates as the real numbers change.

The Interplanetary Magnetic Field, or IMF, is the sun's magnetic field traveling through space as part of the solar wind. Two numbers from RTSW data matter most for aurora hunting.

IMF Bz (The Direction)

Bz measures the north-south direction of the magnetic field. When Bz points south (showing as a negative number), it connects with Earth’s magnetic field near the poles and creates the conditions needed for an aurora.

• What to look for: Look for a negative Bz number. The further below zero the number goes, the higher your chances of seeing a display.
• Good conditions: A Bz of -10 nT or lower.
• Best conditions: A Bz of -15 nT or even lower (such as -20 nT). Deeply negative numbers produce the strongest, most vibrant auroras.

IMF Bt (The Strength)

Bt measures the total strength of the incoming solar magnetic field. The aurora is much more likely to happen when this field presses strongly against Earth’s magnetic shield.

• What to look for: In contrast to Bz, you want the Bt number to be as high as possible.
• Good conditions: A Bt higher than 10 nT shows decent energy.
• Best conditions: A Bt higher than 20 nT means a large amount of solar energy is arriving, significantly increasing your chances of seeing a spectacular show.

Solar Wind

Just as you feel the wind more strongly when walking outside on a breezy day, the same principle applies to the solar wind.

The faster the solar wind travels toward Earth, the more energy it transfers into the planet’s magnetic field. This increases the likelihood that the aurora will become brighter, more dynamic, and more visible in the night sky.

Monitoring solar wind speed is an important factor for predicting when and where the Northern Lights will put on their most spectacular displays.

Real-time metrics summary

Clouds forecast

The clouds coverage forecast will help you to find the best position to spot the Northern Lights. With it, you can locate and predict the cloud’s movement and your chance to see the lights will be higher when the sky is clear. Cloud is the main enemy for Aurora hunters. No matter how strong the aurora is if the sky is fully covered by clouds you chance will decrease.

Why real-time data beats the Kp index

The Kp-index is the most used metric for Northern Lights hunting. It measures disturbances in Earth’s magnetic field on a scale from 0 to 9. The higher the number, the further south the lights can be seen from the North Pole.

While the Kp-index is incredibly popular, it has a major flaw: it is not a real-time measurement. Instead, it estimates aurora strength in 3-to-6-hour blocks. Because of this lag, the Kp-index is often inaccurate for active, minute-by-minute hunting.

If you are already traveling within the Aurora Zone, the Kp-index is not the value you should be watching. To avoid missing a sudden show, you need to understand and follow real-time aurora forecasts instead.

Long-term aurora forecast

Long-term aurora forecasts on Hello Aurora app helps you to plan your trip. They provide key metrics such as the aurora strength from the last-sun rotation and KP index.

While these forecasts give valuable guidance, aurora conditions can change quickly, just like the weather. To ensure you don’t miss a display, always verify real-time data on the day of your hunt, giving you the most precise, actionable information for a successful aurora chase.

How to see the Northern Lights tonight?

You can find the aurora borealis in the high-altitude regions such as Iceland, Alaska, Canada, Northern Norway, Sweden and Finland and many great places that are located above 60° latitude. 

The best way to see the Northern lights is to find where the cloud's coverage is clear, and the possibility to see them will be higher on that location.

Besides the cloud coverage, another thing to have in mind when hunting is that you should be careful with light pollution.

Can you see the aurora in the city?

Many may have wondered if it’s possible to see the aurora in the city? Yes, from our top aurora hotspot in Iceland data in 2025 pointed out that you can actually see the aurora in the city.

And if you are already in the Northern Lights countries, turn on the notification on the Hello Aurora app and we will send you the notification when the aurora activity has increased or when someone already spotted the aurora so you will never miss the aurora again!

When can I see the Northern Lights?

Aurora is active all year but you will not be able to see them during the summertime due to brightness, especially in the Nordic country where they have almost 24 hours of daylight in the summer so winter is the ideal season.

By winter, we meant from late August to the beginning of April. Thanks to the short sunlight hours, you might be able to spot the northern light starting from when the sun is completely set. 

Which aurora app should I use?

Hello Aurora was built by an indie developer focused on one goal: helping you actually find the aurora, not just read about it. Every chart, alert and forecast inside is tuned for real-world hunting, not generic weather forecasting.

Photographers, arctic guides and first-time travelers all use the app. It pulls real-time metrics such as Aurora Strength, RTSW, Bz, Bt and cloud cover into one place, then sends you a live alert the moment conditions turn favorable, or the moment someone nearby spots the lights.

Hello Aurora includes:

• Real-time aurora forecasts with simple, easy to read metrics
• Live alerts when the Northern Lights are visible near you
• Community reports where users share photos and locations in real time
• An ad-free experience with aurora spotting maps and live photo sharing

More than 300,000 users worldwide now use Hello Aurora to plan their trips and catch the lights.

Summary

Reading an aurora forecast comes down to a handful of numbers: Aurora Strength, Real-Time Solar Wind, IMF Bz and Bt, solar wind speed and cloud cover. Together they tell you far more, and far sooner, than the Kp index ever could. Whether you’re planning your first trip to see the lights or you’re a dedicated aurora chaser, Hello Aurora is the must have Northern Lights tracker app you need for 2026 ensures you never miss a display. With live notifications, real-time data, and a growing community, it’s the ultimate companion for your Northern Lights adventure 💚

Frequently asked questions

Q: What is Real-Time Solar Wind (RTSW)?
A: RTSW is live data on the solar wind heading toward Earth, measured by NOAA's SOLAR-1 satellite at the L1 point, about 1 million miles from Earth. It typically gives 15 to 60 minutes of lead time before the solar wind arrives.

Q: Is the Kp index a good way to track the Northern Lights?
A: The Kp index updates only every 3 to 6 hours, so it misses fast changes. Real-time metrics like Aurora Strength and RTSW are far more useful for active hunting.

Q: What Bz and Bt values give the best chance of seeing the aurora?
A: Look for Bz at -10 nT or lower, ideally -15 nT or beyond, and Bt above 20 nT. Together these show a strong, well-aligned solar wind connection with Earth's magnetic field.

Q: Can you see the Northern Lights from a city?
A: Yes, in some cases. Iceland has recorded city-visible displays when Aurora Strength runs high and skies stay clear. Light pollution still lowers your odds, so darker spots remain your best bet.

Q: When is the best time of year to see the Northern Lights?
A: Late August through early April, when nights are long and dark enough in the Nordic countries and other Aurora Zone destinations.