Solar Maximum 2025: What to Expect

Solar Cycle 25 is defying early predictions and ramping up faster than anticipated. As we enter the peak phase known as Solar Maximum, the sun is unleashing more energy, resulting in frequent solar flares and coronal mass ejections. This period promises spectacular auroras at lower latitudes but also poses distinct challenges for our technology-dependent society.

Understanding the 11-Year Cycle

The sun is a massive ball of electrically charged hot gas. As it moves, it generates a powerful magnetic field. Approximately every 11 years, this magnetic field completely flips. The North and South poles switch places. This cycle influences the amount of activity on the solar surface.

We are currently in Solar Cycle 25, which officially began in December 2019. The “Solar Maximum” is the middle of the solar cycle when the sun has the most sunspots. Sunspots are cooler areas on the sun’s surface caused by magnetic fields that inhibit heat transfer. They are the launchpads for solar flares and explosive Coronal Mass Ejections (CMEs).

While initial forecasts suggested Cycle 25 would be mild (similar to the historically weak Cycle 24), reality has proven otherwise. Sunspot counts have consistently exceeded predictions since late 2022.

The Timeline: When is the Peak?

Pinpointing an exact date for Solar Maximum is difficult until after the fact, but scientists have narrowed the window. According to the NOAA Space Weather Prediction Center (SWPC), the peak of solar activity is occurring roughly between late 2024 and early 2026.

Originally, the Solar Cycle 25 Prediction Panel estimated the peak would occur in July 2025 with a peak sunspot number of 115. However, the sun has been more active than those models suggested. Recent months have seen sunspot numbers soar nearly double that estimate. This indicates we are in for a stronger and potentially longer maximum phase.

What This Means for Skywatchers: Global Auroras

The most visible effect of Solar Maximum is the expansion of the auroral oval. During periods of low activity, the Northern Lights (Aurora Borealis) and Southern Lights (Aurora Australis) are usually confined to the extreme polar regions.

During Solar Maximum, intense geomagnetic storms push these lights toward the equator.

  • The May 2024 Event: In May 2024, Earth experienced a G5 (Extreme) geomagnetic storm. This was the strongest storm since 2003. It pushed auroras as far south as Florida, Mexico, and northern India.
  • Frequency: During 2025, you can expect more “G4” and “G5” class storms. This significantly increases the chances of seeing auroras in places like the United Kingdom, the northern United States, and central Europe.
  • Colors: High-altitude oxygen shines red during intense storms, which is why recent displays have featured vibrant reds and pinks visible even in light-polluted suburbs.

Risks to Technology and Infrastructure

While auroras are beautiful, the magnetic energy driving them can be disruptive. The influx of charged particles interacts with Earth’s magnetosphere and atmosphere.

Satellite Operations

As the atmosphere absorbs energy from solar storms, it heats up and expands. This increases atmospheric drag on satellites in low-Earth orbit.

  • Starlink and Debris: Companies like SpaceX must use onboard thrusters more frequently to keep Starlink satellites in orbit. In severe cases, satellites can lose altitude and burn up.
  • Collision Avoidance: Increased drag changes the trajectory of space junk, making it harder for ground control to predict and avoid collisions between debris and active spacecraft.

GPS and Communication

Solar flares emit X-rays and extreme ultraviolet radiation that ionize the upper layers of Earth’s atmosphere. This ionization acts as a barrier or a scattering agent for radio waves.

  • Radio Blackouts: High-frequency (HF) radio signals used by aviation and maritime industries can be blacked out for hours on the sunlit side of Earth during a strong flare (classed as X-class flares).
  • GPS Errors: The increased density of the ionosphere slows down GPS signals. This timing error translates to location inaccuracies, which affects everything from precision agriculture (automated tractors) to drone navigation.

The Power Grid

The most severe risk is to electrical power grids. When a CME hits Earth, it induces Geomagnetically Induced Currents (GICs) in the ground. These currents flow through long conductors like power lines.

  • Transformer Damage: GICs can overheat large power transformers, potentially causing permanent damage.
  • Historical Context: In March 1989, a solar storm caused the entire Hydro-Québec power grid to collapse in 90 seconds, leaving 6 million people without power. Grid operators today are better prepared, but the risk remains for localized outages during extreme events in 2025.

How to Track Solar Activity

You do not need a telescope to know when the sun is acting up. Several reliable sources provide real-time data.

  1. NOAA Space Weather Prediction Center: This is the official source for U.S. government alerts. Look for the “Planetary K-index.” A Kp index of 7, 8, or 9 indicates a major storm is in progress.
  2. SpaceWeatherLive: An excellent app and website that aggregates data on solar flares and auroral activity.
  3. Glendale App / Aurora Reach: These community-driven apps alert you when users near you report seeing the aurora.

Frequently Asked Questions

Is Solar Maximum dangerous to human health? No. Earth’s atmosphere and magnetic field protect humans on the ground from solar radiation. Astronauts in space or passengers on high-altitude polar flights may receive slightly higher doses of radiation, but airlines often reroute flights during extreme solar events to mitigate this.

Will the internet go down during Solar Maximum? A total “Internet Apocalypse” is highly unlikely. While undersea cables are generally resilient, the repeaters that boost signals could theoretically be vulnerable. However, the most likely disruptions would be temporary satellite internet outages (like Starlink) or GPS glitches, not a global terrestrial internet collapse.

Does Solar Maximum cause hotter weather on Earth? The sun’s total irradiance (brightness) varies very slightly (about 0.1%) between solar minimum and maximum. While this does add a tiny amount of energy to the Earth system, it is not the primary driver of current global warming trends. The climate impact of the solar cycle is negligible compared to human-driven greenhouse gas emissions.

When will Solar Cycle 25 end? After the peak in 2025⁄2026, activity will gradually wane. We expect to reach the next Solar Minimum, where sunspots become rare again, around 2030.