ASK TOM WHY: Are wind speeds higher during the day than they are at night?

Dear Tom,

I believe, in general, wind speeds increase during the day and are definitely stronger than at night. Am I correct?

— Cary Tucker



Dear Cary,

You are correct. Sun-induced heating during the day disappears with the onset of darkness and, if the weather is not stormy, winds typically fade to calm or near calm around sunset. Nighttime cooling sets up a situation in which cooler, denser air collects near the ground and milder temperatures prevail above, effectively shunting winds that reach the ground during the day away from the surface. Those winds continue to blow through the night several hundred feet aloft. With the return of sunlight and heating the next morning, winds return to the surface. The effect is less pronounced during the winter because of a lower sun angle and less heat input from sunlight (and more overall storminess than in summer), but it’s still there.

One thought on “ASK TOM WHY: Are wind speeds higher during the day than they are at night?

  1. Dear Tom,

    I have a wind data from Tropical zone near equator (Ethiopia). I found from the data that the day time wind speed is less than the night time! The data in the northern country behaves day time wind speed stronger than the night time. However, the other data was from the central part of the country, the great rift valley crossing the country from North-East to South. I wonder how this could happen?


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