what's the right ( a hour ) or ( an hour )?

[Mohammadata]

Hello Mr. Torsten & all people ,

when I want to say ( a hour ) I feel it is mistake because the pronounce is hard.

but I feel the right is ( an hour ).

please , help me to know the right ?

Thank you

Yours sincerely ,

Mohammad

[Jamie (K)]

It's "an hour". The letter H in the word "hour" is not pronounced, so it begins with a vowel sound.