- Solar Cycle 25 peaked in 2024–2025 with sunspot counts far exceeding NOAA's predicted maximum of 115 (actual counts reached 200+).
- The solar maximum phase brings 100–200 G2+ geomagnetic storms per year, compared to 20–50 during solar minimum.
- Aurora visible at unusually low latitudes (New York, London, Tokyo) occurs primarily during solar maximum years.
- The elevated activity window for Cycle 25 is expected to continue through 2026–2027 before declining toward solar minimum.
- Solar Cycle 25 has already produced several historic storms, including the May 2024 G5 event visible from all 50 US states.
- Each solar cycle lasts approximately 11 years — the next solar minimum is expected around 2030–2031.
What Is a Solar Cycle?
The sun is not a static ball of fire. It follows an approximately 11-year cycle of magnetic activity that directly controls how much aurora we see on Earth. At the heart of this cycle is the sun's magnetic field, which flips polarity roughly every 11 years. This cycle drives the rise and fall of sunspots, solar flares, and coronal mass ejections (CMEs) — the events responsible for geomagnetic storms and aurora.
The primary metric for tracking the solar cycle is the sunspot number. Sunspots are temporary dark regions on the sun's surface where intense magnetic field lines break through the photosphere. More sunspots mean more magnetic complexity, more energy stored in the corona, and more frequent eruptions. At solar minimum, the sun may go days or weeks without a single sunspot. At solar maximum, the daily count can exceed 200.
Scientists have been systematically tracking sunspot numbers since 1755, when Swiss astronomer Rudolf Wolf established the numbering system still used today. Each cycle is numbered sequentially — we are currently in Solar Cycle 25, which began in December 2019 with the transition from the quiet minimum of Cycle 24.
The cycle follows a broadly predictable arc: a slow rise from minimum (typically 4–5 years), a peak lasting 2–3 years, and a gradual decline back to minimum. However, the details — the exact peak height, the timing of the maximum, and the distribution of major eruptions — remain difficult to predict with precision. This is where Solar Cycle 25 has surprised everyone.
Source: NOAA SWPC — Solar Cycle Progression.
Solar Cycle 25: The Surprise
In December 2019, an expert panel convened by NOAA and NASA issued their official prediction for Solar Cycle 25: a relatively weak cycle with a maximum sunspot number of approximately 115, peaking in July 2025. This would have placed Cycle 25 in the same range as its predecessor, Cycle 24, which was one of the weakest cycles in a century.
The sun had other plans. By mid-2023, sunspot counts were already running well above the predicted curve. By 2024, the monthly smoothed sunspot number had climbed past 150 — and the sun kept accelerating. Actual peak counts exceeded 200, making Cycle 25 one of the strongest solar cycles in recent decades and roughly comparable to Cycle 23, which peaked in 2001.
This was not merely an academic surprise. The difference between a sunspot maximum of 115 and one exceeding 200 translates directly into more frequent and more powerful geomagnetic storms — and therefore, dramatically more aurora visible from mid-latitude locations.
Solar Cycle 25 also exhibited the double-peak phenomenon, a pattern seen in many previous cycles where the sunspot count reaches an initial peak, dips briefly, and then rises to a second peak that can be equal to or higher than the first. This behavior is thought to be related to the fact that the sun's northern and southern hemispheres do not reach maximum activity simultaneously. The result is an extended period of elevated activity rather than a single sharp peak.
Why were the predictions so far off? The solar dynamo — the mechanism deep within the sun that generates its magnetic field — remains one of the most challenging systems in astrophysics to model. Current models use the strength of the polar magnetic field near solar minimum as a proxy for the next cycle's strength. This method works reasonably well for average cycles but struggles with outliers. Cycle 25 has demonstrated that our predictive capabilities, while improving, still have significant limitations.
What This Means for Aurora
The connection between solar activity and aurora is direct and measurable. More sunspots mean more active regions on the sun. More active regions produce more solar flares and coronal mass ejections (CMEs). More CMEs directed at Earth produce more geomagnetic storms. And more geomagnetic storms produce more aurora.
During solar maximum, the numbers shift dramatically. G2–G3 geomagnetic storms (KP 6–7) occur on a roughly monthly basis, compared to once or twice a year during solar minimum. G4 storms (KP 8) happen multiple times per year. And even G5 events (KP 9) — the extreme storms that push aurora down to subtropical latitudes — occur roughly once a year during the most active phases.
The practical result is that aurora becomes visible at lower latitudes far more frequently. During solar minimum, you typically need to be above 60° geomagnetic latitude to see aurora regularly. During solar maximum, strong displays routinely reach 50° geomagnetic latitude, and G4–G5 events push the auroral oval below 45° — bringing northern lights to cities like New York, London, Munich, and Tokyo.
The May 2024 G5 storm was the showcase event of this solar maximum. It was the strongest geomagnetic storm since the Halloween storms of 2003, and it produced aurora visible from every US state, including Hawaii. Social media was flooded with photos from locations that hadn't seen the northern lights in decades — southern California, central Texas, northern Mexico, and Mediterranean Europe. This single event demonstrated what solar maximum makes possible.
There is also the concept of "aurora lag" — the tendency for CME frequency to remain elevated for 1–2 years after the sunspot count has begun to decline from its peak. This happens because coronal holes, which produce high-speed solar wind streams, tend to grow larger during the declining phase of the cycle. These recurring streams can produce multi-day geomagnetic storms every 27 days as they rotate with the sun. For aurora watchers, this means 2026–2027 remains an excellent window for northern lights, even if sunspot numbers have started to ease from their peak values.
For a detailed breakdown of what each storm level means, see our guide to geomagnetic storms from G1 to G5.
How Long Will the Good Aurora Last?
This is the question every aurora chaser is asking: how long do we have? The answer draws on both the physics of solar cycles and the historical record.
The peak phase of a solar cycle — the period of maximum sunspot activity — typically lasts 2–3 years. For Cycle 25, with its peak in approximately 2024–2025, this means the highest level of activity spans roughly from late 2023 through 2026. However, the transition from maximum to declining phase is gradual, not abrupt.
Historical patterns from Cycles 23 and 24 are instructive. Solar Cycle 23 peaked in 2001 with a sunspot maximum of about 180, but produced its most famous geomagnetic storms — the Halloween storms — in October–November 2003, well into the declining phase. Some of the best aurora of that entire cycle came 2 years after the sunspot peak. Solar Cycle 24, despite being a weak cycle overall, produced the St. Patrick's Day storm of March 2015 and continued generating occasional G3+ storms through 2017.
The pattern is clear: strong aurora does not end when sunspot numbers peak. The declining phase of the solar cycle, spanning roughly 2027–2029 for Cycle 25, will still produce significant geomagnetic storms. Activity will be less frequent than at peak, but G3 and even G4 events will still occur. The aurora simply becomes harder to catch, not impossible.
Solar minimum for Cycle 25 is expected around 2030–2031. During minimum, aurora retreats to the highest latitudes — northern Scandinavia, Iceland, northern Canada, and Alaska become the primary viewing zones again, and mid-latitude sightings become rare events rather than monthly occurrences.
The best advice for anyone who has been thinking about chasing the northern lights: don't wait. The 2024–2027 window represents the best aurora viewing conditions we will see until Solar Cycle 26 ramps up in the early 2030s. Every month of delay narrows the window.
Making the Most of Solar Maximum
Knowing that we are in a period of elevated solar activity is only useful if you take concrete steps to catch the aurora when it appears. Geomagnetic storms are inherently unpredictable in their exact timing — a CME launched from the sun today might produce aurora in 2–4 days, or it might miss Earth entirely. The key is to be prepared when conditions align.
Set up aurora alerts. Real-time notification when geomagnetic activity reaches your location's threshold is the single most important tool. Storms often peak in the middle of the night, and the difference between catching a G3 storm and sleeping through it comes down to whether you had an alert set. The Revon app monitors solar wind data and sends push notifications calibrated to your exact coordinates — whether you need a KP 3 in Tromsø or a KP 7 in London.
Plan trips to high-latitude destinations. While solar maximum brings aurora to lower latitudes more often, the most reliable viewing is still at high latitudes. Northern Norway (Tromsø, Lofoten), Finnish Lapland (Rovaniemi, Inari), Iceland, northern Sweden (Abisko, Kiruna), and northern Canada (Yellowknife, Whitehorse) remain the top destinations. At these locations, even modest G1 storms produce vivid overhead displays.
Target the equinox months. March and September–October consistently produce more geomagnetic storms than other months. This is the Russell–McPherron effect — a geometric alignment between Earth's magnetic axis and the sun's magnetic field that makes the magnetosphere more susceptible to solar wind coupling during equinox periods. Combining the equinox boost with solar maximum activity creates the best possible conditions. For more detail on seasonal timing, see our guide to the best time to see the northern lights.
Even mid-latitude locations have realistic chances. During this solar maximum window, aurora chasers in the UK, northern France, northern Germany, the Netherlands, and the northern United States (from Oregon to Maine) have legitimate opportunities to see the northern lights multiple times per year. You don't need to fly to the Arctic — you need clear skies, a dark location away from city lights, and a good alert system.
Don't forget the southern hemisphere. Solar maximum affects both polar regions equally. Australia, New Zealand, southern Chile, and Argentina see increased aurora australis activity during the same window. The May 2024 G5 storm produced spectacular southern lights visible from Melbourne, Sydney, and the entire South Island of New Zealand.
Frequently Asked Questions
What is solar maximum?
Solar maximum is the peak of the approximately 11-year solar cycle, when the sun's magnetic activity reaches its highest level. During solar maximum, the sun produces more sunspots, solar flares, and coronal mass ejections (CMEs). These events drive geomagnetic storms on Earth, which produce aurora. More solar activity means more frequent and intense aurora visible at lower latitudes.
When is the next solar maximum?
Solar Cycle 25 peaked in approximately 2024–2025, with sunspot counts far exceeding NOAA's original predictions. Solar cycles often show a "double peak" pattern, and Cycle 25 appears to have exhibited this behavior. The elevated activity is expected to continue through 2026–2027 before declining toward solar minimum around 2030–2031.
Does solar maximum guarantee more northern lights?
It significantly increases the probability but doesn't guarantee aurora on any specific night. During solar maximum, G2+ geomagnetic storms occur roughly 100–200 times per year compared to 20–50 during solar minimum. This means more opportunities, but you still need clear skies, darkness, and correct timing. An aurora alert app helps you catch the events when they happen.
How long does solar maximum last?
The peak phase of a solar cycle typically lasts 2–3 years, though activity can remain elevated for 1–2 years beyond the sunspot peak. For Solar Cycle 25, this means enhanced aurora opportunities from roughly 2024 through 2027. The exact timing varies because solar cycles are not perfectly predictable.
Will Solar Cycle 25 produce another Carrington Event?
The likelihood of a Carrington-class (G5+) event in any given solar cycle is estimated at 1–2%. Solar Cycle 25 has already produced several G5 events, including the historic May 2024 storm. While another extreme event is possible, it is not expected with any certainty. The key takeaway is that even moderate solar cycles produce enough G2–G4 storms for excellent aurora viewing.
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