Cosmic radiation on flights from Miami (MIA) to New York (JFK)
A flight from Miami International Airport to John F. Kennedy International Airport at 35,000 ft, about 2 h 18 min in the air, receives about 0.00694 mSv (6.94 µSv) of cosmic radiation: about 7% of a chest X-ray. That is the FAA's CARI-7 model run for this route with the solar conditions of August 2026.
Updated · solar conditions of August 2026
- Dose
- 6.94 µSv0.00694 mSv
- Time in the air
- 2 h 18 minestimated
- Dose rate
- 3.0 µSv/haverage, 35,000 ft
- Chest X‑rays
- 0.069at 0.1 mSv each
Key facts: MIA → JFK
| Dose, standard flight | 0.00694 mSv (6.94 µSv) |
|---|---|
| Time in the air | 2 h 18 min, estimated from distance and prevailing winds |
| Cruise altitude | 35,000 ft |
| Average dose rate | 3.0 µSv/h |
| Great-circle distance | 1,757 km (1,092 mi) |
| Furthest from the equator | 40.6°N |
| Solar conditions | August 2026 |
The standard flight is CARI-7, the FAA Civil Aerospace Medical Institute's model, run on the dev machine for this route: 35,000 ft, 2 h 18 min in the air (climb 25 min, cruise 96 min, descent 17 min), effective dose per ICRP Publication 103. How it's calculated.
How the sun changes the dose on MIA → JFK
The sun's 11-year cycle moves this number. With the same 2 h 18 min at 35,000 ft, the flight would have received 0.00824 mSv in April 2020, when the sun was quiet and more galactic cosmic rays reached the atmosphere, and 0.00566 mSv in January 2026, near solar maximum: 46% more at the quiet end. In August 2026 it is 0.00694 mSv.
The numbers behind the chart
| Month | Dose | Dose |
|---|---|---|
| January 2016 | 7.49 µSv | 0.00749 mSv |
| April 2016 | 7.65 µSv | 0.00765 mSv |
| July 2016 | 7.63 µSv | 0.00763 mSv |
| October 2016 | 7.83 µSv | 0.00783 mSv |
| January 2017 | 7.9 µSv | 0.0079 mSv |
| April 2017 | 8.04 µSv | 0.00804 mSv |
| July 2017 | 7.93 µSv | 0.00793 mSv |
| October 2017 | 7.88 µSv | 0.00788 mSv |
| January 2018 | 7.98 µSv | 0.00798 mSv |
| April 2018 | 8.14 µSv | 0.00814 mSv |
| July 2018 | 8.11 µSv | 0.00811 mSv |
| October 2018 | 8.23 µSv | 0.00823 mSv |
| January 2019 | 7.93 µSv | 0.00793 mSv |
| April 2019 | 8.21 µSv | 0.00821 mSv |
| July 2019 | 8.13 µSv | 0.00813 mSv |
| October 2019 | 8.21 µSv | 0.00821 mSv |
| January 2020 | 8.18 µSv | 0.00818 mSv |
| April 2020 | 8.24 µSv | 0.00824 mSv |
| July 2020 | 8.19 µSv | 0.00819 mSv |
| October 2020 | 8.19 µSv | 0.00819 mSv |
| January 2021 | 7.99 µSv | 0.00799 mSv |
| April 2021 | 8.22 µSv | 0.00822 mSv |
| July 2021 | 8.07 µSv | 0.00807 mSv |
| October 2021 | 8.09 µSv | 0.00809 mSv |
| January 2022 | 7.97 µSv | 0.00797 mSv |
| April 2022 | 7.9 µSv | 0.0079 mSv |
| July 2022 | 7.39 µSv | 0.00739 mSv |
| October 2022 | 7.58 µSv | 0.00758 mSv |
| January 2023 | 7.05 µSv | 0.00705 mSv |
| April 2023 | 7.12 µSv | 0.00711 mSv |
| July 2023 | 6.78 µSv | 0.00678 mSv |
| October 2023 | 6.81 µSv | 0.00681 mSv |
| January 2024 | 6.48 µSv | 0.00648 mSv |
| April 2024 | 6.64 µSv | 0.00664 mSv |
| July 2024 | 6.68 µSv | 0.00668 mSv |
| October 2024 | 5.95 µSv | 0.00595 mSv |
| January 2025 | 6.14 µSv | 0.00614 mSv |
| April 2025 | 6.15 µSv | 0.00615 mSv |
| July 2025 | 6.09 µSv | 0.00609 mSv |
| October 2025 | 6.22 µSv | 0.00622 mSv |
| January 2026 | 5.66 µSv | 0.00566 mSv |
| April 2026 | 6.31 µSv | 0.00631 mSv |
| July 2026 | 6.68 µSv | 0.00668 mSv |
| August 2026 | 6.94 µSv | 0.00694 mSv |
How cruise altitude changes the dose
Flown at 31,000 ft instead, the same flight would receive 0.00508 mSv, 27% less than at 35,000 ft; at 41,000 ft it would receive 0.00995 mSv, 43% more. Same route, same time in the air, same month: only the air overhead changes.
Try it: change the altitude and the month
Every combination is its own CARI-7 run for MIA → JFK, with the same 2 h 18 min in the air. It is still a standard flight, not yours: the app calculates your exact flight.
Every combination as a table (µSv)
| Altitude | Jan 2016 | Jan 2017 | Jan 2018 | Jan 2019 | Jan 2020 | Jan 2021 | Jan 2022 | Jan 2023 | Jan 2024 | Jan 2025 | Jan 2026 | Aug 2026 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 31,000 ft | 5.48 | 5.77 | 5.83 | 5.79 | 5.97 | 5.83 | 5.82 | 5.16 | 4.76 | 4.51 | 4.17 | 5.08 |
| 33,000 ft | 6.45 | 6.8 | 6.87 | 6.83 | 7.04 | 6.88 | 6.86 | 6.07 | 5.59 | 5.3 | 4.89 | 5.98 |
| 35,000 ft | 7.49 | 7.9 | 7.98 | 7.93 | 8.18 | 7.99 | 7.97 | 7.05 | 6.48 | 6.14 | 5.66 | 6.94 |
| 37,000 ft | 8.57 | 9.05 | 9.15 | 9.09 | 9.38 | 9.15 | 9.13 | 8.06 | 7.41 | 7 | 6.46 | 7.93 |
| 39,000 ft | 9.68 | 10.2 | 10.3 | 10.3 | 10.6 | 10.3 | 10.3 | 9.09 | 8.34 | 7.88 | 7.25 | 8.95 |
| 41,000 ft | 10.8 | 11.4 | 11.5 | 11.4 | 11.8 | 11.5 | 11.5 | 10.1 | 9.26 | 8.74 | 8.03 | 9.95 |
The return flight: JFK → MIA
JFK → MIA receives 0.00732 mSv at 35,000 ft, 5% more than MIA → JFK, over about 2 h 25 min in the air against 2 h 18 min. The two directions take about the same time: the route runs mostly north–south, across the prevailing westerly winds rather than into them.
What 6.94 µSv compares with
| Compared with | Its dose | This flight is |
|---|---|---|
| Chest X-Ray | 0.1 mSv | about 7% of a chest X-ray |
| Dental X-Ray | 0.005 mSv | about a dental X-ray |
| Background Radiation (Daily) | 0.008 mSv | about 87% of a day's natural background radiation |
| Mammogram | 0.4 mSv | about 2% of a mammogram |
| Head CT Scan | 2 mSv | about 1% of a head CT scan |
| Eating a Banana | 0.0001 mSv | about 69 bananas |
The comparison values are the ones the FlightDose app uses.
Why your flight will differ
- Altitude. Flown at 31,000 ft instead, the same flight would receive 0.00508 mSv, 27% less than at 35,000 ft; at 41,000 ft it would receive 0.00995 mSv, 43% more. Same route, same time in the air, same month: only the air overhead changes.
- Time in the air. Every extra 30 minutes on this route adds about 1.5 µSv. Headwinds, holding and routing change it by tens of minutes on a long flight.
- The month. The sun's 11-year cycle swings this route's dose by about 46% between quiet and active years.
- The track. Airlines fly tracks that bend with the jet stream, not the exact great circle; a track further from the equator collects more.
- Solar storms. A rare solar radiation storm can add to the dose for hours; CARI-7's monthly figures don't include one.
FlightDose calculates your exact flight.
Your date, your altitude, your time in the air, with live space weather, and a running total against the limits that matter to you.
Other routes from MIA
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