Cosmic radiation on flights from Honolulu, Oahu (HNL) to Los Angeles (LAX)

Reverse: Los Angeles → Honolulu, Oahu

A flight from Daniel K. Inouye International Airport to Los Angeles International Airport at 35,000 ft, about 4 h 47 min in the air, receives about 0.0105 mSv (10.5 µSv) of cosmic radiation: about a tenth 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
10.5 µSv0.0105 mSv
Time in the air
4 h 47 minestimated
Dose rate
2.2 µSv/haverage, 35,000 ft
Chest X‑rays
0.1at 0.1 mSv each

Key facts: HNL → LAX

Dose, standard flight0.0105 mSv (10.5 µSv)
Time in the air4 h 47 min, estimated from distance and prevailing winds
Cruise altitude35,000 ft
Average dose rate2.2 µSv/h
Great-circle distance4,108 km (2,553 mi)
Furthest from the equator33.9°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, 4 h 47 min in the air (climb 25 min, cruise 245 min, descent 17 min), effective dose per ICRP Publication 103. How it's calculated.

HNLLAX
Great-circle route, shaded from 1.6 µSv/h to 2.9 µSv/h. Shading is modelled from the monthly dose-rate grid; totals are CARI-7.

How the sun changes the dose on HNL → LAX

The sun's 11-year cycle moves this number. With the same 4 h 47 min at 35,000 ft, the flight would have received 0.0114 mSv in April 2020, when the sun was quiet and more galactic cosmic rays reached the atmosphere, and 0.00937 mSv in January 2026, near solar maximum: 22% more at the quiet end. In August 2026 it is 0.0105 mSv.

Dose for this flight at 35,000 ft, quarterly
0 µSv5 µSv10 µSv15 µSv20162018202020222024202611.4 µSv9.37 µSv10.5 µSv
0 µSv5 µSv10 µSv15 µSv20162020202411.4 µSv9.37 µSv10.5 µSv
The numbers behind the chart
MonthDoseDose
January 201610.9 µSv0.0109 mSv
April 201611 µSv0.011 mSv
July 201611 µSv0.011 mSv
October 201611.2 µSv0.0112 mSv
January 201711.2 µSv0.0112 mSv
April 201711.3 µSv0.0113 mSv
July 201711.2 µSv0.0112 mSv
October 201711.2 µSv0.0112 mSv
January 201811.3 µSv0.0113 mSv
April 201811.4 µSv0.0114 mSv
July 201811.4 µSv0.0114 mSv
October 201811.4 µSv0.0114 mSv
January 201911.2 µSv0.0112 mSv
April 201911.4 µSv0.0114 mSv
July 201911.4 µSv0.0114 mSv
October 201911.4 µSv0.0114 mSv
January 202011.4 µSv0.0114 mSv
April 202011.4 µSv0.0114 mSv
July 202011.4 µSv0.0114 mSv
October 202011.4 µSv0.0114 mSv
January 202111.3 µSv0.0113 mSv
April 202111.4 µSv0.0114 mSv
July 202111.3 µSv0.0113 mSv
October 202111.3 µSv0.0113 mSv
January 202211.3 µSv0.0112 mSv
April 202211.2 µSv0.0112 mSv
July 202210.8 µSv0.0108 mSv
October 202211 µSv0.011 mSv
January 202310.6 µSv0.0106 mSv
April 202310.6 µSv0.0106 mSv
July 202310.3 µSv0.0103 mSv
October 202310.4 µSv0.0104 mSv
January 202410.1 µSv0.0101 mSv
April 202410.2 µSv0.0102 mSv
July 202410.3 µSv0.0103 mSv
October 20249.64 µSv0.00964 mSv
January 20259.8 µSv0.0098 mSv
April 20259.81 µSv0.00981 mSv
July 20259.76 µSv0.00976 mSv
October 20259.88 µSv0.00988 mSv
January 20269.37 µSv0.00937 mSv
April 20269.96 µSv0.00996 mSv
July 202610.3 µSv0.0103 mSv
August 202610.5 µSv0.0105 mSv

How cruise altitude changes the dose

Flown at 31,000 ft instead, the same flight would receive 0.00784 mSv, 25% less than at 35,000 ft; at 41,000 ft it would receive 0.0144 mSv, 37% 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 ft7.84 µSv
  • 33,000 ft9.14 µSv
  • 35,000 ft10.5 µSv
  • 37,000 ft11.8 µSv
  • 39,000 ft13.1 µSv
  • 41,000 ft14.4 µSv

Try it: change the altitude and the month

Every combination is its own CARI-7 run for HNL → LAX, with the same 4 h 47 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 ft8.168.388.438.48.538.438.427.917.567.347.017.84
33,000 ft9.519.769.829.799.949.829.819.218.818.558.179.14
35,000 ft10.911.211.311.211.411.311.310.610.19.89.3710.5
37,000 ft12.312.612.712.712.912.712.711.911.411.110.611.8
39,000 ft13.714.114.114.114.314.114.113.312.712.311.713.1
41,000 ft1515.415.515.415.715.515.514.513.813.412.814.4

The return flight: LAX → HNL

LAX → HNL receives 0.0119 mSv at 35,000 ft, 14% more than HNL → LAX, over about 5 h 25 min in the air against 4 h 47 min. The return takes 38 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
  • HNL → LAX10.5 µSv
  • LAX → HNL11.9 µSv

Cosmic radiation on Los Angeles → Honolulu, Oahu flights

What 10.5 µSv compares with

Compared withIts doseThis flight is
Chest X-Ray0.1 mSvabout a tenth of a chest X-ray
Dental X-Ray0.005 mSvabout 2.1 dental X-rays
Background Radiation (Daily)0.008 mSvabout a day's natural background radiation
Mammogram0.4 mSvabout 3% of a mammogram
Head CT Scan2 mSvabout 1% of a head CT scan
Eating a Banana0.0001 mSvabout 105 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 0.00784 mSv, 25% less than at 35,000 ft; at 41,000 ft it would receive 0.0144 mSv, 37% 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 22% 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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