Cosmic radiation on flights from New York (JFK) to Miami (MIA)

Reverse: Miami → New York

A flight from John F. Kennedy International Airport to Miami International Airport at 35,000 ft, about 2 h 25 min in the air, receives about 0.00732 mSv (7.32 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
7.32 µSv0.00732 mSv
Time in the air
2 h 25 minestimated
Dose rate
3.0 µSv/haverage, 35,000 ft
Chest X‑rays
0.073at 0.1 mSv each

Key facts: JFK → MIA

Dose, standard flight0.00732 mSv (7.32 µSv)
Time in the air2 h 25 min, estimated from distance and prevailing winds
Cruise altitude35,000 ft
Average dose rate3.0 µSv/h
Great-circle distance1,757 km (1,092 mi)
Furthest from the equator40.6°N
Solar conditionsAugust 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 25 min in the air (climb 25 min, cruise 103 min, descent 17 min), effective dose per ICRP Publication 103. How it's calculated.

JFKMIA
Great-circle route, shaded from 2.5 µSv/h to 3.5 µSv/h. Shading is modelled from the monthly dose-rate grid; totals are CARI-7.

How the sun changes the dose on JFK → MIA

The sun's 11-year cycle moves this number. With the same 2 h 25 min at 35,000 ft, the flight would have received 0.00866 mSv in April 2020, when the sun was quiet and more galactic cosmic rays reached the atmosphere, and 0.00599 mSv in January 2026, near solar maximum: 45% more at the quiet end. In August 2026 it is 0.00732 mSv.

Dose for this flight at 35,000 ft, quarterly
0 µSv5 µSv10 µSv2016201820202022202420268.66 µSv5.99 µSv7.32 µSv
0 µSv5 µSv10 µSv2016202020248.66 µSv5.99 µSv7.32 µSv
The numbers behind the chart
MonthDoseDose
January 20167.89 µSv0.00789 mSv
April 20168.06 µSv0.00806 mSv
July 20168.03 µSv0.00803 mSv
October 20168.24 µSv0.00824 mSv
January 20178.31 µSv0.00831 mSv
April 20178.46 µSv0.00846 mSv
July 20178.35 µSv0.00835 mSv
October 20178.29 µSv0.00829 mSv
January 20188.4 µSv0.0084 mSv
April 20188.56 µSv0.00856 mSv
July 20188.53 µSv0.00853 mSv
October 20188.65 µSv0.00865 mSv
January 20198.35 µSv0.00835 mSv
April 20198.64 µSv0.00864 mSv
July 20198.55 µSv0.00855 mSv
October 20198.64 µSv0.00864 mSv
January 20208.6 µSv0.0086 mSv
April 20208.66 µSv0.00866 mSv
July 20208.62 µSv0.00861 mSv
October 20208.62 µSv0.00861 mSv
January 20218.4 µSv0.0084 mSv
April 20218.64 µSv0.00864 mSv
July 20218.49 µSv0.00849 mSv
October 20218.51 µSv0.00851 mSv
January 20228.38 µSv0.00838 mSv
April 20228.32 µSv0.00832 mSv
July 20227.79 µSv0.00779 mSv
October 20227.98 µSv0.00798 mSv
January 20237.43 µSv0.00743 mSv
April 20237.5 µSv0.0075 mSv
July 20237.15 µSv0.00715 mSv
October 20237.18 µSv0.00718 mSv
January 20246.84 µSv0.00684 mSv
April 20247 µSv0.007 mSv
July 20247.05 µSv0.00705 mSv
October 20246.29 µSv0.00629 mSv
January 20256.48 µSv0.00648 mSv
April 20256.49 µSv0.00649 mSv
July 20256.43 µSv0.00643 mSv
October 20256.57 µSv0.00657 mSv
January 20265.99 µSv0.00599 mSv
April 20266.67 µSv0.00667 mSv
July 20267.05 µSv0.00705 mSv
August 20267.32 µSv0.00732 mSv

How cruise altitude changes the dose

Flown at 31,000 ft instead, the same flight would receive 0.00536 mSv, 27% less than at 35,000 ft; at 41,000 ft it would receive 0.0105 mSv, 43% more. Same route, same time in the air, same month: only the air overhead changes.

Dose for this flight by cruise altitude, August 2026
  • 31,000 ft5.36 µSv
  • 33,000 ft6.31 µSv
  • 35,000 ft7.32 µSv
  • 37,000 ft8.36 µSv
  • 39,000 ft9.43 µSv
  • 41,000 ft10.5 µSv

Try it: change the altitude and the month

Every combination is its own CARI-7 run for JFK → MIA, with the same 2 h 25 min in the air. It is still a standard flight, not yours: the app calculates your exact flight.

Every combination as a table (µSv)
AltitudeJan 2016Jan 2017Jan 2018Jan 2019Jan 2020Jan 2021Jan 2022Jan 2023Jan 2024Jan 2025Jan 2026Aug 2026
31,000 ft5.776.076.146.16.286.146.135.445.024.774.415.36
33,000 ft6.87.167.237.197.417.247.226.415.915.65.186.31
35,000 ft7.898.318.48.358.68.48.387.436.846.485.997.32
37,000 ft9.039.529.629.569.869.639.68.497.827.46.828.36
39,000 ft10.210.810.910.811.110.910.89.588.88.327.679.43
41,000 ft11.31212.11212.412.112.110.79.779.238.4910.5

The return flight: MIA → JFK

MIA → JFK receives 0.00694 mSv at 35,000 ft, 5% less than JFK → MIA, over about 2 h 18 min in the air against 2 h 25 min. The two directions take about the same time: the route runs mostly north–south, across the prevailing westerly winds rather than into them.

Dose for each direction, standard flight
  • JFK → MIA7.32 µSv
  • MIA → JFK6.94 µSv

Cosmic radiation on Miami → New York flights

What 7.32 µSv compares with

Compared withIts doseThis flight is
Chest X-Ray0.1 mSvabout 7% of a chest X-ray
Dental X-Ray0.005 mSvabout a dental X-ray
Background Radiation (Daily)0.008 mSvabout a day's natural background radiation
Mammogram0.4 mSvabout 2% of a mammogram
Head CT Scan2 mSvabout 1% of a head CT scan
Eating a Banana0.0001 mSvabout 73 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 0.00536 mSv, 27% less than at 35,000 ft; at 41,000 ft it would receive 0.0105 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 45% 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.

Download on the App Store Get it on Google Play

Other routes from JFK

All about John F. Kennedy International Airport

Other routes to MIA

No other routes to MIA are published yet.

Every published route

Questions people ask

All questions