Cosmic radiation on flights from New York (JFK) to São Paulo (GRU)

Reverse: São Paulo → New York

A flight from John F. Kennedy International Airport to São Paulo/Guarulhos–Governor André Franco Montoro International Airport at 35,000 ft, about 9 h 3 min in the air, receives about 0.0201 mSv (20.1 µSv) of cosmic radiation: about a fifth 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
20.1 µSv0.0201 mSv
Time in the air
9 h 3 minestimated
Dose rate
2.2 µSv/haverage, 35,000 ft
Chest X‑rays
0.2at 0.1 mSv each

Key facts: JFK → GRU

Dose, standard flight0.0201 mSv (20.1 µSv)
Time in the air9 h 3 min, estimated from distance and prevailing winds
Cruise altitude35,000 ft
Average dose rate2.2 µSv/h
Great-circle distance7,664 km (4,762 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, 9 h 3 min in the air (climb 25 min, cruise 501 min, descent 17 min), effective dose per ICRP Publication 103. How it's calculated.

JFKGRU
Great-circle route, shaded from 1.7 µSv/h to 4.0 µSv/h. Shading is modelled from the monthly dose-rate grid; totals are CARI-7.

How the sun changes the dose on JFK → GRU

The sun's 11-year cycle moves this number. With the same 9 h 3 min at 35,000 ft, the flight would have received 0.0221 mSv in April 2020, when the sun was quiet and more galactic cosmic rays reached the atmosphere, and 0.0179 mSv in January 2026, near solar maximum: 24% more at the quiet end. In August 2026 it is 0.0201 mSv.

Dose for this flight at 35,000 ft, quarterly
0 µSv10 µSv20 µSv30 µSv20162018202020222024202622.1 µSv17.9 µSv20.1 µSv
0 µSv10 µSv20 µSv30 µSv20162020202422.1 µSv17.9 µSv20.1 µSv
The numbers behind the chart
MonthDoseDose
January 201621 µSv0.021 mSv
April 201621.2 µSv0.0212 mSv
July 201621.2 µSv0.0212 mSv
October 201621.5 µSv0.0215 mSv
January 201721.6 µSv0.0216 mSv
April 201721.8 µSv0.0218 mSv
July 201721.6 µSv0.0216 mSv
October 201721.6 µSv0.0216 mSv
January 201821.7 µSv0.0217 mSv
April 201821.9 µSv0.022 mSv
July 201821.9 µSv0.0219 mSv
October 201822.1 µSv0.0221 mSv
January 201921.6 µSv0.0216 mSv
April 201922.1 µSv0.0221 mSv
July 201921.9 µSv0.0219 mSv
October 201922.1 µSv0.0221 mSv
January 202022 µSv0.022 mSv
April 202022.1 µSv0.0221 mSv
July 202022 µSv0.022 mSv
October 202022 µSv0.022 mSv
January 202121.7 µSv0.0217 mSv
April 202122.1 µSv0.0221 mSv
July 202121.9 µSv0.0219 mSv
October 202121.9 µSv0.0219 mSv
January 202221.7 µSv0.0217 mSv
April 202221.6 µSv0.0216 mSv
July 202220.8 µSv0.0208 mSv
October 202221.1 µSv0.0211 mSv
January 202320.3 µSv0.0203 mSv
April 202320.4 µSv0.0204 mSv
July 202319.8 µSv0.0198 mSv
October 202319.9 µSv0.0199 mSv
January 202419.3 µSv0.0193 mSv
April 202419.6 µSv0.0196 mSv
July 202419.7 µSv0.0197 mSv
October 202418.4 µSv0.0184 mSv
January 202518.8 µSv0.0187 mSv
April 202518.8 µSv0.0188 mSv
July 202518.7 µSv0.0187 mSv
October 202518.9 µSv0.0189 mSv
January 202617.9 µSv0.0179 mSv
April 202619.1 µSv0.0191 mSv
July 202619.7 µSv0.0197 mSv
August 202620.1 µSv0.0201 mSv

How cruise altitude changes the dose

Flown at 31,000 ft instead, the same flight would receive 0.015 mSv, 25% less than at 35,000 ft; at 41,000 ft it would receive 0.0276 mSv, 38% 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 ft15 µSv
  • 33,000 ft17.5 µSv
  • 35,000 ft20.1 µSv
  • 37,000 ft22.7 µSv
  • 39,000 ft25.3 µSv
  • 41,000 ft27.6 µSv

Try it: change the altitude and the month

Every combination is its own CARI-7 run for JFK → GRU, with the same 9 h 3 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 ft15.716.116.216.216.416.216.215.214.51413.415
33,000 ft18.318.818.918.919.218.918.917.716.916.415.617.5
35,000 ft2121.621.721.62221.721.720.319.318.817.920.1
37,000 ft23.724.424.624.524.924.624.522.921.821.220.222.7
39,000 ft26.427.227.427.327.727.427.325.524.323.522.425.3
41,000 ft28.929.83029.930.43029.927.926.525.724.527.6

The return flight: GRU → JFK

GRU → JFK receives 0.0207 mSv at 35,000 ft, 3% more than JFK → GRU, over about 9 h 14 min in the air against 9 h 3 min. The return takes 11 min longer: its track runs against the prevailing westerly winds at cruise altitude. Cosmic radiation builds up with every minute aloft, so the longer direction collects more of it along the same path.

Dose for each direction, standard flight
  • JFK → GRU20.1 µSv
  • GRU → JFK20.7 µSv

Cosmic radiation on São Paulo → New York flights

What 20.1 µSv compares with

Compared withIts doseThis flight is
Chest X-Ray0.1 mSvabout a fifth of a chest X-ray
Dental X-Ray0.005 mSvabout 4 dental X-rays
Background Radiation (Daily)0.008 mSvabout 2.5 days of natural background radiation
Mammogram0.4 mSvabout 5% of a mammogram
Head CT Scan2 mSvabout 1% of a head CT scan
Eating a Banana0.0001 mSvabout 201 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 0.015 mSv, 25% less than at 35,000 ft; at 41,000 ft it would receive 0.0276 mSv, 38% 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 1.1 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 24% 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.

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