Solar Maximum 2025 is the expected peak of solar activity in Solar Cycle 25, characterized by heightened sunspots, solar flares, and coronal mass ejections. This peak is anticipated around mid to late 2025, coinciding with the Sun’s magnetic field flip. Such solar activity may influence Canadian climate patterns by potentially affecting weather systems.
We asked Hossein Bonakdari, Associate Professor, Civil Engineering at the Faculty of Engineering about this phenomenon.
What is the solar cycle?
Bonakdari: The Solar Cycle is an 11-year pattern where the Sun’s activity changes, like a heartbeat. Sometimes the Sun is calm, with fewer dark spots called sunspots, and sometimes it’s super active, with lots of them. This happens because the Sun’s magnetic field flips every 11 years, like switching from north to south. When the Sun is most active, around the middle of the cycle, we see more sunspots and bursts of energy, like solar flares, which are like giant explosions on the Sun. For example, we’re in Solar Cycle 25 now, which started in December 2019 and will likely be most active around mid-2025.
Why does the solar maximum matter?
Bonakdari: During Solar Maximum, solar flares and coronal mass ejections (CMEs) can damage satellite electronics or increase atmospheric drag, causing satellites to deorbit. Satellites are critical for communication, navigation, and weather forecasting, but they are vulnerable to solar storms. A notable example occurred in February 2022, when a geomagnetic storm caused the loss of 38 out of 49 SpaceX Starlink satellites to burn up upon re-entry. Solar storms can induce geomagnetic currents in Earth’s power grids, which deliver electricity to homes and businesses. These currents can overload transformers, leading to blackouts. A significant historical event was the March 1989 blackout in Quebec, Canada, where a solar storm caused a 9-hour power outage for 6 million people. In addition, solar storms ionize Earth’s upper atmosphere, interfering with radio signals and GPS accuracy. In December 2005, solar X-rays caused a 10-minute disruption in satellite-to-ground and GPS signals, demonstrating the potential for even brief outages to impact critical operations.
Can solar activity influence Earth’s climate?
Bonakdari: The Sun is the primary energy source for Earth's climate system, and its activity can influence atmospheric and oceanic conditions. Solar activity, like sunspots and solar flares, does influence Earth's climate, but its effect is relatively minor. Given the small magnitude of solar-driven climate effects, the Solar Maximum is unlikely to have significantly influenced summer 2025’s temperatures. Recent summers, such as 2023 and 2024, experienced record-breaking heat, with global temperatures reaching unprecedented levels. Summer 2025’s climate is expected to follow similar patterns, with high temperatures and extreme weather events like heatwaves, heavy rainfall, or droughts, primarily attributed to human-driven climate change rather than solar activity. This potential intense heat and climate extremes of summer 2025 are more closely tied to carbon dioxide and methane emissions, which trap heat in the atmosphere, than to the Sun’s current activity peak.
Has this summer’s sun had more of an impact on health with higher UV?
Bonakdari: Solar Maximum increases UV radiation, but the change is minimal. Studies show that UV levels at Earth’s surface rise by less than 1-2% from Solar Minimum to Solar Maximum, as measured by satellite data over multiple solar cycles NASA Science - Solar Variability and Terrestrial Climate. This increase is due to higher Total Solar Irradiance (TSI), which includes UV, but the overall variation in TSI is less than 0.1% over the 11-year cycle Skeptical Science - Solar Activity & Earth's Climate. For summer 2025, this translates to a very small uptick in UV exposure, not enough to alter health risks on its own significantly.
“The Canadian Arctic is warming almost four times faster than the rest of the world”
Hossein Bonakdari
— Associate Professor, Civil Engineering at the Faculty of Engineering
Is Canada’s Electrical Grid Prepared for the Next Solar Storm?
Bonakdari: Canada’s power system stretches across forests, cities, and remote regions, and it faces a hidden threat from space: solar storms. These powerful bursts from the Sun, known as coronal mass ejections (CMEs), can send huge waves of energy toward Earth. When they hit, they can create geomagnetic storms, which push strong electric currents into the ground. These currents, called geomagnetically induced currents (GICs), can overload power lines and damage transformers, sometimes within minutes. Canada is especially at risk because we sit under the part of Earth’s atmosphere that gets hit hardest by these storms. While power companies have made improvements, like installing sensors and systems to slow down power flow during a storm, there are still weak spots. Many of the transformers in use today are decades old and not designed for these types of solar events.
Can Solar Activity Skew Climate Data in the Canadian Arctic?
Bonakdari: The Canadian Arctic is warming almost four times faster than the rest of the world. This makes it one of the most fragile and fast-changing regions on Earth. Some people wonder if changes in the Sun’s activity could be part of the cause. It’s true that the Sun can slightly change how much energy reaches Earth, and sometimes this affects the upper atmosphere. But when it comes to long-term warming in the Arctic, the main cause is human activity, especially the burning of fossil fuels that release carbon dioxide (CO₂) and other greenhouse gases. That’s why we need to separate short-term effects from the Sun from the much larger, ongoing warming caused by humans—which means reducing CO₂ emissions is more urgent than ever.