Letter Riddles

I've shared some riddlebees already, in which each line gives you the clue you need to find a letter, and then you put those letters together to find the answer.  Similarly, there riddles where the answer is a single letter. Sometimes the clue is just a single sentence, but sometimes they are long clues, as you can see in the selection below:

What occurs once in a second, once in a minute, twice annually, but never in February?

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The letter N.

You can see me twice in any day, but not once in the morning or in the night.

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I am the letter A.

You'll see me in New York and New Orleans, and I'm in the middle of every crowd; you'll never find me on the beach, but I'm in every ocean. Who am I?

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I am the letter O.

What can you always find in the middle of nowhere?

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The letter H.

I'm always in a hurry, and you can see me but not hear me in a fight. Who am I?

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I am the letter H.

The gust of the wildest storm I can change to a welcome guest; in the North or the South, I'm unknown, but am found in the East and the West.

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The letter E.