Real-time radiation and space weather, explained
This free real-time radiation monitor provides live reporting on global ionizing radiation levels, solar weather conditions, and geomagnetic activity. All data is sourced directly from NOAA's Space Weather Prediction Center (SWPC), the world's authoritative source for space weather forecasting and solar event reporting. The Kp index, storm scales and alerts refresh every 2 minutes and the minute-by-minute solar-wind files every 5 minutes, giving you continuous access to live space weather telemetry without any registration, API keys, or fees.
The Kp Index chart displays the last 3 days of planetary geomagnetic activity and NOAA’s forecast for the next 3 days, measured on a 0 to 9 scale. This index is essential for understanding when geomagnetic storms may affect GPS accuracy, radio communications, power grid stability, and aurora visibility. A Kp value of 5 or above indicates a geomagnetic storm. The color-coded bar chart makes it easy to spot storm periods at a glance, and the status badge provides an instant summary of current geomagnetic conditions — from quiet to extreme storm levels.
Earth’s magnetic shield, live
The large picture at the top of the page shows Earth’s magnetic field, the magnetosphere, in the solar wind. The outer edge is the magnetopause, the boundary where the pressure of the solar wind balances the pressure of Earth’s field. On the Sun side it normally sits about 10 to 11 Earth radii (roughly 65,000 to 70,000 km) from the planet. A fast or dense solar wind pushes it closer; a calm wind lets it relax outward. Where the wind meets the field head-on it first passes through a bow shock, where it slows down and heats up, before it flows around the magnetopause and stretches Earth’s field into a long tail on the night side.
The shape of the magnetopause is calculated in your browser with the Shue et al. (1998) model. Its inputs are the live solar-wind speed and proton density, which give the dynamic pressure (with a typical 4 % helium share added), and the north-south component of the magnetic field, Bz. The ring at 6.6 Earth radii is geostationary orbit, home of weather and communication satellites. When a storm compresses the magnetopause to that distance, those satellites are briefly outside Earth’s protective field. This happened in the strongest storms, and the superstorm of 10 May 2024 pushed the boundary in to about 5 Earth radii.
When Bz points south, the solar wind’s field links up with Earth’s and energy flows in along the field lines to the poles, which is what lights the aurora. The pink streaks in the picture show that leak: the more negative Bz is, the more of them. The bow shock, the field lines and the moving particles are schematic, the animation runs about 50 times faster than reality, and the measurements come from the satellite at L1, so the wind you see reaches Earth roughly 30 to 60 minutes later. The Storm demo button shows a severe storm for comparison; it is not live data.
Solar Wind & Magnetometer Reporting
The solar wind stream comes from the satellite NOAA uses at the L1 Lagrange point, approximately 1.5 million kilometres upstream of Earth (today NOAA’s SOLAR-1, with older spacecraft as backups). Speed and density are mapped directly to the animation: faster solar wind makes faster-moving particles, and higher proton density makes more of them. When solar wind speeds exceed 500 km/s, the particles shift from cyan to yellow, and above 700 km/s they turn red, providing an immediate visual warning of elevated conditions.
The magnetometer Bz timeline tracks the north-south component of the interplanetary magnetic field over the past six hours. When Bz turns negative (southward), it enables magnetic reconnection with Earth's magnetosphere, allowing solar wind energy to couple more efficiently into our magnetic field. Extended periods of strongly negative Bz are the primary driver of geomagnetic storms, making this one of the most important parameters for space weather forecasting.
Worldwide Radiation Map & Live Sensor Network
The interactive world map displays modeled ground-level radiation for 61 locations worldwide — from major capitals to famous radiological anomalies: Pripyat (Chernobyl exclusion zone), Fukushima, Ramsar in Iran (the world's highest natural background, driven by radium-rich hot springs), Guarapari's monazite beaches in Brazil, and the thorium belts of Kerala and Yangjiang. Click any station for a full breakdown: dose rate, annual projection, cosmic-ray latitude and altitude factors, live geomagnetic modulation, geology notes, and everyday comparisons (bananas, chest X-rays, flight hours). A region selector jumps between continents, the station picker ranks locations by current level, and the NOAA OVATION aurora oval can be overlaid live. The map goes truly fullscreen with all controls available.
Ground-level radiation estimates are calculated using a physics-based model that combines known geological baselines per city with real-time cosmic ray modulation data. Higher geomagnetic latitude increases cosmic ray exposure due to weaker magnetic shielding, and elevated Kp index values modulate the cosmic ray intensity reaching Earth's surface. While these are modeled estimates rather than direct sensor readings, they use the same real NOAA data that drives professional space weather reporting systems.
Free Radiation Monitor — No Signup Required
This real-time radiation monitor is completely free to use with no account creation, no ads, and no data collection. It runs entirely in your browser using client-side JavaScript and public NOAA APIs. Whether you are a space weather enthusiast, a radio amateur monitoring HF propagation conditions, a researcher tracking geomagnetic storm impacts, or simply curious about current radiation levels around the world, this tool provides professional-grade radiation monitoring in an accessible, visually engaging format. It is one of over 100 free browser-based tools available at jasperbernaers.com — all built with the same commitment to real data, zero friction, and beautiful design.
Radiation and dose basics
What is μSv/h, and what is a normal level?
Microsieverts per hour (μSv/h) is a dose rate: how much radiation dose a person would receive per hour at that spot. Natural background is typically 0.05 to 0.3 μSv/h, depending on the rocks underground, radon and altitude. Thresholds for an alarm differ per national network, so compare a reading with the usual level for that place rather than with one fixed number.
What is a normal yearly dose?
The worldwide average from natural sources is about 2.4 mSv a year (UNSCEAR): roughly 1.3 mSv from radon, 0.5 mSv from rocks and soil, 0.4 mSv from cosmic rays and 0.3 mSv from food and drink. Medical imaging adds about 0.6 mSv on average worldwide, and more in countries with heavy CT use. The occupational limit for radiation workers is 20 mSv a year, averaged over five years.
What dose is dangerous?
Below about 100 mSv the extra cancer risk is too small to measure directly; radiation protection assumes roughly 0.5% extra lifetime cancer risk per 100 mSv. An acute dose of about 1 Sv (1,000 mSv) causes radiation sickness, and around 4–5 Sv is fatal for about half of people without treatment. Even the highest point on this map, Ramsar at about 1 μSv/h, adds up to under 10 mSv a year.
Alpha, beta and gamma
Alpha particles (helium nuclei) are stopped by paper or skin but are harmful when inhaled or swallowed. Beta particles (electrons) pass through skin but are stopped by a few millimetres of aluminium. Gamma rays need lead or thick concrete. Environmental monitors mostly measure gamma, the main external dose. At flight altitude, neutrons from cosmic rays add a significant share.
Do bananas really contain radiation?
Yes: a small fraction of the potassium in a banana is radioactive potassium-40. Eating one gives about 0.1 μSv, the informal “banana equivalent dose”. A day of normal background is about 20 bananas, a chest X-ray about 200, and a transatlantic flight about 400. The station panel on the map shows each city’s dose rate in bananas per day.
Space weather
What is solar flux (sfu)?
The solar flux index measures the Sun’s radio output at 2,800 MHz (10.7 cm), measured daily at the Dominion Radio Astrophysical Observatory in Penticton, Canada. It runs from about 65 sfu at solar minimum to 200–300 sfu or more around solar maximum, and tracks the Sun’s ultraviolet output, which matters for HF radio propagation and satellite drag.
What is the Kp index?
Kp is a 0–9 measure of global geomagnetic disturbance, derived every three hours from 13 magnetometer stations between 44° and 60° geomagnetic latitude. Kp 5 is a minor storm (G1), Kp 7 a strong storm (G3), Kp 8 severe (G4) and Kp 9 extreme (G5). Storms can degrade GPS accuracy, HF radio and satellite operations and, in extreme cases, power grids.
What do the NOAA R, S and G scales mean?
NOAA rates space weather on three 0–5 scales: R for radio blackouts caused by X-ray flares, S for solar radiation storms caused by energetic protons (relevant to astronauts and polar flights), and G for geomagnetic storms, the same activity the Kp index measures. 0 means no event in progress.
Can a solar storm affect my health?
Not on the ground: the atmosphere and the Earth’s magnetic field absorb it, which is why the ground estimates on the map barely move during storms. The risk is for astronauts and for crews on polar flights during solar particle events, and for infrastructure such as GPS, radio, satellites and power grids — the 1989 Québec blackout was caused by a geomagnetic storm.
Where can I see the northern lights?
It depends on Kp. At Kp 3 the aurora usually stays at high latitudes (Iceland, northern Norway, Alaska). At Kp 5 it can reach Scotland, Denmark and southern Canada, and at Kp 7 or more it can be seen in parts of central Europe and the northern United States. Turn on the aurora oval layer on the map for NOAA’s live OVATION forecast, and look north from a dark place.
Natural and man-made hotspots
Highest natural background on Earth
Ramsar, Iran holds the record: radium-rich hot springs give some residents up to about 260 mSv a year. Other well-known areas are the monazite-sand beaches of Guarapari in Brazil, the thorium-rich coast of Kerala in India (up to about 70 mSv a year), Yangjiang in China, and high-altitude cities such as Denver and Bogotá, where more cosmic radiation reaches the ground.
Is Chernobyl still radioactive?
Yes. The 1986 accident spread caesium-137 and strontium-90, both with half-lives of about 30 years, so a little over half of that contamination has decayed since. Central Pripyat typically reads around 1 μSv/h, with hotspots such as the Red Forest far higher, and parts of the exclusion zone will stay restricted for a very long time.
What are radiation levels in Fukushima now?
Most of Fukushima prefecture is back to near-normal levels and most evacuation orders have been lifted. Monitoring posts in towns near the plant mostly read a few tenths of a μSv/h, the remaining restricted zones more, and Tokyo around 0.04 μSv/h. Levels keep falling a few percent a year through decay and weathering. Japan runs thousands of public real-time monitoring posts.
Altitude and flying
Cosmic radiation roughly doubles every 1,500–2,000 metres you climb. At sea level it contributes about 0.03 μSv/h; at cruise altitude (10–12 km) the total dose rate is about 3–8 μSv/h, depending on latitude and solar activity. A transatlantic flight gives roughly 30–60 μSv. In the EU, airlines must assess the dose of aircrew who are likely to receive more than 1 mSv a year.
Data and monitoring networks
How live is the data?
Solar flux, solar wind, Kp, Bz, the R/S/G scales and alerts come from NOAA’s Space Weather Prediction Center. The Kp index, scales and alerts refresh every 2 minutes and the minute-by-minute solar-wind files every 5 minutes; the status light at the top says LIVE, PARTIAL, STALE or OFFLINE, and a missing value shows as a dash, never as a zero. The shield picture shows typical values, labelled as such, until the first data arrives. The ground-level values on the map are modelled: a known geological and altitude baseline per location, adjusted with the live NOAA data, because official ground networks such as EURDEP and RadNet do not offer a free browser API for individual stations. Use them for context, not as measurements.
Official networks and how to check near you
Official readings come from national networks: Europe’s EURDEP (thousands of stations across about 39 countries), the US EPA RadNet, Germany’s BfS ODL network and Belgium’s FANC TELERAD. The CTBTO’s International Monitoring System also measures airborne radioactivity worldwide. Community projects such as Safecast publish millions of open Geiger-counter measurements. In an emergency, always follow your national radiation protection agency.
The magnetic shield picture
What does “Earth radii” mean here?
One Earth radius is 6,371 km. The number on the dotted line is the distance from the centre of the Earth to the sunward edge of its magnetic field. Typical values are 10 to 11, a strong solar wind can push it to 8 or less, and 6.6 is the height of geostationary orbit.
Is it a real measurement of the magnetopause?
No. The measurements are real (solar-wind speed, density and Bz from NOAA’s L1 satellite), but the boundary is calculated from them with an empirical model, so it is an estimate that is usually right to within about a tenth of its size. Satellites that actually cross the boundary measure it directly; this page does not.
What is the Storm demo?
A button that replaces the live values with those of a severe storm (900 km/s, 25 protons per cm³, Bz about −20 nT) so you can see the shield being squeezed and the energy leak. It is labelled as a demo and changes nothing else on the page.
Using the dashboard
Map markers, regions and full screen
Markers are coloured and sized by modelled dose rate, from green (low) through cyan, yellow and orange to red; known hotspots such as Chernobyl, Fukushima and Ramsar are flagged. Use the region and station drop-downs to jump around, click a marker for details, and use the full-screen button above the map.
The dashboard is free, with no signup, no ads and no tracking cookies.
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