What's the first tune I should learn on the Tin Whistle is a question I hear all the time. I always recommend that you learn songs that you already know such as "Old Macdonald" and "Twinkle Twinkle Little Star" and you can learn those on the TinWhistle.com However, the best "tune" as in an Irish melody and not a children's song to learn on the Tin Whistle in my opinion is "Dawn of the Day."
Dawn of the Day is an easy tune that only uses the first octave. Plus, you can get by without playing any cuts or ornamentation and it sounds good as a slow air or a march. Also, it’s a beautiful tune that most people involved in Irish music will know since almost ever Irish musician learns this tune as one of their firsts. If you wish to learn it on the Tin Whistle, check out my lesson here.
If you interested in learning the Tin Whistle please check out my site here.
Here is the sheet music for the tune if you just want to give it a try!