Solar Storm Flight Radiation: How Much Extra? (October 2026)

In November 2025, the most powerful solar storm in nearly 20 years slammed into Earth’s magnetic field, triggering widespread auroras and raising an important question for anyone flying that week: how much extra radiation do passengers actually absorb during a solar storm? The headlines were dramatic, and if you were boarding a transatlantic flight that day, you might have wondered whether you were about to receive a concerning dose of cosmic radiation.

The short answer is reassuring. Even during a significant solar storm, the extra radiation a passenger receives on a single commercial flight is small, typically adding between 20 and 100 microsieverts on top of the normal flight dose. For context, that is roughly equivalent to one or two chest X-rays, and far below any threshold for acute health effects.

Our team has dug into the peer-reviewed research from institutions like NOAA, ESA, the Health Physics Society, and studies published in the Journal of Geophysical Research to give you the precise numbers. We will walk you through what happens at 35,000 feet during a solar event, what the actual dose data shows, and why you probably do not need to change your travel plans.

The Quick Answer: Extra Radiation on Flights During Solar Storms

During a moderate solar storm, passengers on a typical 8-hour flight at cruising altitude receive roughly 30 to 100 additional microsieverts beyond normal cosmic radiation. During a severe Ground Level Enhancement (GLE), that extra dose can spike to 200 to 600 microsieverts over a 2 to 3 hour period on polar routes.

For comparison, a standard chest X-ray delivers about 20 microsieverts, a dental X-ray gives you 5 microsieverts, and an abdominal CT scan exposes you to roughly 8,000 microsieverts. The average person on the ground receives about 3,000 microsieverts (3 millisieverts) of background radiation every year from natural sources.

The bottom line: a single flight during a solar storm does not pose a meaningful health risk to occasional passengers. The concern is real for airline crew who accumulate thousands of flight hours per year, and we will address that distinction below.

What Happens During a Solar Storm at Flight Altitude

Solar storms come in several flavors, and understanding the basics helps explain why they matter for aviation. The two key players are solar flares (sudden bursts of electromagnetic radiation from the Sun’s surface) and coronal mass ejections or CMEs (massive clouds of charged plasma hurled into space). When these events send high-energy protons and other particles streaming toward Earth, they are called Solar Energetic Particle events, or SEPs.

At ground level, you are well protected. Earth’s atmosphere provides shielding equivalent to about 10 meters of water, and the planet’s magnetic field deflects most charged particles toward the poles. But at 35,000 to 40,000 feet, where commercial aircraft cruise, that atmospheric shield is dramatically thinner. There is roughly 75 percent less atmosphere above you compared to standing at sea level.

This is where the physics gets interesting. When solar energetic particles slam into the thin upper atmosphere at aircraft cruising altitudes, they create what physicists call nucleonic-electromagnetic-muon showers. Think of it as a cascade of secondary particles that spreads outward from each incoming proton. These secondary particles are what actually expose passengers and crew to radiation, not the original solar protons themselves.

The same effect happens with galactic cosmic rays (GCR), the constant background radiation from deep space that is always present at flight altitudes. During a solar storm, a burst of solar energetic particles gets layered on top of that normal galactic cosmic ray background, creating a temporary spike in radiation dose rates.

Polar Routes: Why Some Flights Are Riskier Than Others

Earth’s magnetic field does not protect all flight routes equally. The magnetic field channels charged particles toward the north and south magnetic poles, which means flights passing through high-latitude regions (typically above 60 degrees latitude) face significantly higher radiation exposure during a solar storm.

Popular transpolar routes connecting North America to Asia, such as flights from New York to Tokyo or Chicago to Seoul, pass directly through these high-latitude zones. A study by Mishev and Usoskin published in the Journal of Geophysical Research modeled radiation levels during the September 10, 2017 GLE 72 event and found that a Helsinki-to-Osaka polar flight received dramatically higher doses than a Helsinki-to-New York mid-latitude route during the same event.

This is why airlines pay such close attention to space weather forecasts for transpolar operations. The numbers we are about to share assume worst-case polar routing, which represents the upper end of what any passenger might realistically experience.

Normal Radiation Dose on a Commercial Flight

Before we can talk about extra radiation during a solar storm, we need to establish the baseline. Every time you step on a commercial flight, you are exposed to elevated cosmic radiation. This is true regardless of solar activity, and it is a completely normal part of air travel that has been studied for decades.

At typical cruising altitude (35,000 to 40,000 feet), the normal radiation dose rate ranges from 3 to 8 microsieverts per hour. The exact rate depends on altitude, latitude, and where we are in the roughly 11-year solar cycle. During solar maximum, when the Sun is most active, the enhanced solar wind actually pushes some galactic cosmic rays away from Earth, slightly reducing normal background radiation at flight altitudes.

Here is what that translates to for common flight durations:

A 2-hour domestic flight delivers approximately 6 to 16 microsieverts. A 6-hour transatlantic flight (such as New York to London) adds about 30 to 50 microsieverts. A 12-hour long-haul flight (such as Los Angeles to Tokyo) results in roughly 60 to 100 microsieverts. These are baseline numbers under normal space weather conditions.

Altitude matters significantly. Radiation dose rates at 30,000 feet are roughly half what they are at 40,000 feet. This is why supersonic aircraft like the Concorde, which cruised at 60,000 feet, had much higher radiation exposure concerns, and why the FAA has specific guidance for aircraft operating above 50,000 feet.

How Much Extra Radiation Passengers Get on a Flight During a Solar Storm

Now for the question you came here for. The exact amount of extra radiation passengers receive during a solar storm depends on the severity of the event, the flight route, and the altitude. But we can give you concrete numbers based on documented Ground Level Enhancement events.

During a typical moderate solar storm, dose rates at aircraft cruising altitudes can increase from the normal 3 to 8 microsieverts per hour up to 10 to 30 microsieverts per hour. That means a 6-hour transatlantic flight during a moderate event might deliver an extra 20 to 60 microsieverts on top of the normal dose.

During a severe Ground Level Enhancement, the numbers jump dramatically. The most studied recent example is GLE 72, which occurred on September 10, 2017, triggered by an X8.2-class solar flare. Research from the Global Neutron Monitor Network showed that dose rates at 40,000 feet over polar regions spiked to 100 to 200 microsieverts per hour for a period of roughly 2 to 3 hours.

For a passenger on a polar route during peak GLE 72 conditions, the total extra radiation dose for those 2 to 3 hours would have been approximately 400 to 600 microsieverts. That is roughly equivalent to 20 to 30 chest X-rays or about 15 percent of the average annual background radiation dose. It is notable but still well below any threshold for acute radiation sickness, which begins at roughly 500,000 microsieverts (500 millisieverts) in a single exposure.

The November 2025 solar storm was classified as a G4 (Severe) geomagnetic storm on the NOAA scale and was accompanied by a significant SEP event. Based on preliminary data from neutron monitors, dose rates at altitude during the peak of this event likely reached similar levels to GLE 72 on polar routes. ESA reported that an Airbus A320 experienced avionics anomalies potentially linked to the event, underscoring that while human health effects were minimal, the technological impacts were real.

Historical GLE Events and Their Aviation Impact

Since systematic monitoring began in the 1940s, scientists have recorded 73 Ground Level Enhancement events. The most powerful of these for aviation radiation was the October 1989 series during solar cycle 22, when multiple GLEs occurred in rapid succession. Dose estimates for crew on polar flights during that period reached levels that would now trigger occupational radiation protection protocols.

The famous Carrington Event of 1859, the strongest solar storm in recorded history, occurred before aviation existed. If a similar event struck today, models suggest dose rates at cruising altitude could briefly exceed 1,000 microsieverts per hour. However, events of that magnitude are extremely rare, estimated to occur once every several hundred years based on ice core analysis.

The Health Physics Society notes that a true superflare capable of delivering dangerous radiation doses to passengers would be extraordinarily rare, with an estimated frequency of once every several million years. For practical purposes, no documented solar event has ever produced radiation levels at aircraft altitudes that would cause acute health effects in passengers.

Radiation Dose Comparison: Flights, Medical Procedures, and Daily Life

Numbers in microsieverts can feel abstract without context. Here is a comparison to help you understand what these doses actually mean relative to radiation you encounter in everyday life.

A dental X-ray delivers about 5 microsieverts. A chest X-ray delivers about 20 microsieverts. A normal 6-hour flight delivers about 40 microsieverts. A mammogram delivers roughly 400 microsieverts. A flight during a severe solar storm (2-3 hours at peak) adds about 400 to 600 microsieverts. An abdominal CT scan delivers approximately 8,000 microsieverts. One full year of natural background radiation on the ground totals about 3,000 microsieverts.

For a fun scale reference, eating a single banana exposes you to about 0.1 microsieverts due to naturally radioactive potassium-40. You would need to eat roughly 4,000 bananas to match the extra radiation from flying during a severe solar storm. Radiation scientists actually use this as an informal comparison called the Banana Equivalent Dose.

What these comparisons show is that even the maximum realistic radiation dose from a solar storm flight is comparable to a single medical imaging procedure. It is not zero, but it fits comfortably within the range of radiation exposures that people routinely experience without concern.

Is It Safe to Fly During a Solar Storm?

For the vast majority of passengers, the answer is a clear yes. The extra radiation from a solar storm on a single flight is small enough that it does not meaningfully change your health risk profile. You receive more radiation driving to the airport if you live at altitude (Denver residents, for example, receive about 1,500 extra microsieverts per year from cosmic radiation at ground level alone).

For frequent flyers who log dozens of long-haul flights per year, the cumulative picture is more nuanced. If you fly 200,000 miles annually, your normal cosmic radiation dose from flying alone adds roughly 500 to 1,000 microsieverts per year. A solar storm during one of those flights would add a modest increment, but the cumulative annual total is still well within the range of normal variation in background radiation.

Flight Crew Radiation Exposure: The Real Story

The group that genuinely needs to pay attention to solar storm radiation is airline crew. Studies published in peer-reviewed journals show that commercial flight crew members receive average annual effective doses of 1.2 to 2.0 millisieverts (1,200 to 2,000 microsieverts) from occupational cosmic radiation exposure. That is roughly three times the average annual background dose at ground level.

This is why the FAA, the European Union, and the International Commission on Radiological Protection (ICRP) all classify airline crew as occupationally exposed radiation workers. In the EU, pregnant crew members are subject to specific dose limits, with a maximum of 1 millisievert to the fetus during the declared pregnancy.

A severe solar storm can add a meaningful increment to crew exposure. During GLE 72, a single polar flight during peak conditions could have added 400 to 600 microsieverts to a crew member’s annual total. This is why some airlines have protocols to reroute or delay polar flights during major SEP events. The November 2025 event reportedly prompted several transpolar flight reroutes by major carriers.

What About the November 2025 Airbus A320 Incident?

One detail that generated significant media attention was the reported grounding of an Airbus A320 during the November 2025 solar storm due to avionics anomalies. This highlights an important distinction that many articles gloss over: the radiation effects on aircraft electronics are a separate concern from radiation effects on human health.

High-energy particles can cause single event upsets, commonly called bit flips, in aircraft computer systems. A single particle striking a microchip can change a 0 to a 1 in memory, potentially causing software errors. This is a known and managed risk in aviation, with redundant systems designed to catch and correct such errors. The A320 incident was an electronics concern, not a human health crisis, and the aircraft was grounded as a precaution.

No passengers were harmed by radiation during the November 2025 event. The flight in question landed safely, and the avionics issue was investigated as a technical matter. This is a good example of how solar storms can affect aviation infrastructure without posing a direct health threat to travelers.

Pregnancy, Solar Storms, and Flying

This is one of the most common concerns we see in forums and PAA questions, and it deserves a direct answer. The Health Physics Society specifically addresses this topic and concludes that even during large solar flares, the radiation dose to a pregnant passenger is not at a level that should cause concern for fetal health.

The ICRP recommends a maximum radiation dose of 1 millisievert (1,000 microsieverts) to the fetus during the entire declared pregnancy. A single transatlantic flight during a moderate solar storm would add roughly 50 to 100 extra microsieverts, well below that threshold. Even during a severe GLE event, the extra dose on a single flight would represent only a fraction of the recommended pregnancy limit.

For pregnant crew members, the calculus is different because of cumulative exposure over hundreds of flights. EU regulations specifically require airlines to reassign pregnant crew members to ground duties once they declare their pregnancy, precisely to manage this cumulative risk. For a pregnant passenger taking one or two flights, the additional radiation from a solar storm is not a medical concern.

That said, if you are pregnant and concerned, there is nothing wrong with checking the space weather forecast before your flight. We will tell you how to do that in the next section.

How Airlines and Regulators Handle Solar Storm Risk

You might wonder whether anyone is actually watching for these events. The answer is yes, and the monitoring infrastructure is extensive. NOAA’s Space Weather Prediction Center in Boulder, Colorado, operates a 24/7 space weather monitoring service that tracks solar flares, CMEs, and SEP events in real time.

When a significant SEP event is detected, airlines receive alerts through the International Civil Aviation Organization (ICAO) space weather advisory system, which became operational in 2019. Major carriers with polar routes have specific protocols that may include rerouting flights to lower latitudes, changing cruising altitude, or in rare cases delaying departure until the SEP event subsides.

The European Space Agency operates the Space Weather Service Portal, which provides radiation dose calculations through a tool called AVIDOS (Aviation Radiation Dosimetry). AVIDOS allows operators to estimate radiation exposure for specific flight routes and solar conditions. ESA is also developing the Vigil mission, planned for launch in 2031, which will station a dedicated space weather monitoring spacecraft at Lagrange Point 5 to provide earlier warning of potentially hazardous solar events.

The FAA’s Civil Aerospace Medical Institute maintains radiation dose estimation models for U.S. commercial aviation and provides guidance to airlines on radiation protection for crew members. The agency recommends that airlines track individual crew member doses and ensure they remain below regulatory limits.

How to Check Space Weather Before Your Flight

If you want to check conditions before you fly, here are the best free resources available to the public. NOAA’s Space Weather Prediction Center (swpc.noaa.gov) provides real-time alerts, forecasts, and a 3-day space weather outlook. ESA’s Space Weather Service Portal (swe.ssa.esa.int) offers European-centric monitoring and forecasts. SpaceWeatherLive.com provides user-friendly real-time data including solar flare classifications and geomagnetic storm scales.

For most passengers, checking these resources is more about curiosity than necessity. Solar storms strong enough to produce meaningful radiation increases at flight altitudes are rare, and when they do occur, airlines already have protocols in place to manage the risk. But if you are a nervous flyer or simply want to know what is happening above your head, these tools can provide valuable context.

Frequently Asked Questions

The Bottom Line on Solar Storm Radiation and Flying

So, how much extra radiation do passengers get on a flight during a solar storm? The honest, data-backed answer is: somewhere between 20 and 100 microsieverts for most events, and up to 400 to 600 microsieverts during the rare, most severe Ground Level Enhancements on polar routes. That is roughly the equivalent of one chest X-ray for a moderate event, or about 20 to 30 chest X-rays for the worst-case scenario during a severe GLE on a polar flight.

Neither scenario comes close to dangerous levels for a one-time exposure. The threshold for acute radiation sickness starts at roughly 500,000 microsieverts delivered in a single dose. The extra radiation from flying during a solar storm is orders of magnitude below that.

What matters more is cumulative exposure over time, which is why the real focus belongs on airline crew and ultra-frequent flyers rather than the occasional passenger. If you fly once or twice a year, a solar storm adds a trivial increment to your overall radiation profile. Your cross-country road trip, your dental visit, and the natural background radiation you absorb just by living on Earth at altitude all contribute far more to your annual dose.

If you are anxious about flying during solar activity, the best thing you can do is check the NOAA Space Weather Prediction Center before your trip. Knowing the actual conditions, rather than relying on sensational headlines, is the most effective way to put the risk in perspective. Solar storms are a real and fascinating phenomenon, but for the average airline passenger, they are not a reason to stay grounded.