Cosmic radiation at 35,000 feet, worldwide
In August 2026, the cosmic radiation dose rate at 35,000 ft ranged from 1.4 µSv/h near the equator to 4.7 µSv/h near the poles: 3.3 times as much. Earth's magnetic field turns cosmic rays away most strongly where it runs parallel to the ground, over the tropics, and least where it dips into the poles, so a route's latitude decides most of its dose.
Updated · solar conditions of August 2026
Dose rate by latitude
The same numbers as the colours, one row per 10° of latitude. The spread within a row is longitude: Earth's magnetic poles sit off its geographic ones, so the same latitude is magnetically further north in some places than others. At 50°N the rate averages 4.6 µSv/h over North America against 4.1 µSv/h over Europe and 3.7 µSv/h over Asia.
A flight's dose is roughly its average rate along the route times its hours in the air. An hour at the equator gives about 1.5 µSv; an hour over the Arctic gives up to 4.7 µSv.
| Latitude | Lowest | Average | Highest |
|---|---|---|---|
| 90°N | 4.7 µSv/h | 4.7 µSv/h | 4.7 µSv/h |
| 80°N | 4.7 µSv/h | 4.7 µSv/h | 4.7 µSv/h |
| 70°N | 4.7 µSv/h | 4.7 µSv/h | 4.7 µSv/h |
| 60°N | 4.6 µSv/h | 4.7 µSv/h | 4.7 µSv/h |
| 50°N | 3.5 µSv/h | 4.1 µSv/h | 4.7 µSv/h |
| 40°N | 2.3 µSv/h | 3.1 µSv/h | 4.5 µSv/h |
| 30°N | 1.7 µSv/h | 2.2 µSv/h | 3.6 µSv/h |
| 20°N | 1.5 µSv/h | 1.8 µSv/h | 2.8 µSv/h |
| 10°N | 1.4 µSv/h | 1.7 µSv/h | 2.0 µSv/h |
| 0° (equator) | 1.5 µSv/h | 1.7 µSv/h | 1.8 µSv/h |
| 10°S | 1.6 µSv/h | 1.8 µSv/h | 2.0 µSv/h |
| 20°S | 1.8 µSv/h | 2.1 µSv/h | 2.5 µSv/h |
| 30°S | 2.0 µSv/h | 2.8 µSv/h | 3.3 µSv/h |
| 40°S | 2.3 µSv/h | 3.6 µSv/h | 4.5 µSv/h |
| 50°S | 3.0 µSv/h | 4.2 µSv/h | 4.7 µSv/h |
| 60°S | 4.0 µSv/h | 4.6 µSv/h | 4.7 µSv/h |
| 70°S | 4.7 µSv/h | 4.7 µSv/h | 4.7 µSv/h |
| 80°S | 4.7 µSv/h | 4.7 µSv/h | 4.7 µSv/h |
| 90°S | 4.7 µSv/h | 4.7 µSv/h | 4.7 µSv/h |
What this map is, and isn't
It is the monthly average for August 2026, computed with the solar conditions of that month. It is not a live map: a solar radiation storm can raise rates at high latitudes for hours, and CARI-7's monthly figures don't include one (more on solar storms). Between the computed points the colours are interpolated, so they show the pattern, not the exact rate over a given city. The route totals on each route page are full CARI-7 flight calculations, not read off this map.
This month's grid as data: /data/v1/grid/2026-08-35000.json.
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