Why Do Pilots Say 'Winds Aloft Are True' When Forecasts Are Often Inaccurate?

It’s important to remember that true north and magnetic north are not the same.

Meg Godlewski

Wednesday, March 19, 2025 at 10:45 AM ET

Verified

Edited By:

Kimberly Johnson

The difference between true and magnetic north measured in degrees is called variation. [Credit: Shutterstock]

Key Takeaways:

When pilots say "winds aloft are true," they mean the wind direction is referenced to true north (the Earth's geographic axis), not magnetic north.
True north and magnetic north are distinct locations, with the difference between them called "variation," which varies geographically and over time.
Winds aloft data are forecasts, which are predictions based on available data, explaining why actual winds at altitude can sometimes differ from the forecast.

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Question: Why do people say, “Winds aloft are true,” when what is forecast is often notoriously inaccurate from what you really experience at altitude? I am a student pilot and this has messed me up several times.

Answer: In this case the word “true” means in reference to “true north” as opposed to magnetic north.

True north, per Chapter 8 of the Pilot’s Handbook of Aeronautical Knowledge (PHAK), is the geographic axis that the Earth rotates about. Think of how a globe is mounted with the posts at the physical north and south poles.