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:

The term "true" in "winds aloft are true" signifies that wind directions are referenced to true north (the Earth's geographic axis), not magnetic north.
The deviation between true north and magnetic north is called variation, a value that differs depending on location.
Winds aloft are provided as forecasts, meaning they are predictions and are therefore susceptible to inaccuracies compared to actual in-flight conditions.

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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.