The Short Answer
YES - if you want to enjoy your honeymoon in a serenely beautiful land of ancient heritage and romantic dreams. NO - if you want to relax on a tropical beach soaking up the hot sun.
The "Castles In the Air" Answer
Let's get one thing straight. Ireland has a mild, damp climate. Mild means it rarely gets very cold, or very hot. Damp means you may get wet. No-one vacations in Ireland for the good weather. (Aside: you may get lucky. Some summers do produce nice, extended bouts of sunshine -- just don't count on it.) So why would anyone have their honeymoon in Ireland? Well, here are the reasons that people who have honeymooned in Ireland usually give:
1. Ireland is a serenely beautiful country
Ireland-lovers are drawn by its natural beauty and -- outside of Dublin, the capital city -- its calm solitude. This peacefulness is found in Ireland's natural environment -- from trickling hillside springs to glorious bays and beaches, but also in its people, and their slower, more relaxed pace of life. When you come to Ireland, you can experience this natural beauty, this serenity, up close. There are literally thousands of beautiful, scenic places in Ireland. This website lists just some of them.
2. Irish Happiness
In Ireland, a popular expression is "I'm happy in my own skin". This means that someone is generally content in life. Irish people use this expression a lot. Indeed, Irish people have consistently been surveyed to be among the happiest people in Europe. Irish people are also quite open and friendly -- they like to talk to visitors and interact with them. If you holiday in Ireland, and meet Irish people, you will find that the happiness of Irish people genuinely rubs off on you.
3. Ireland Has a Rich and Ancient Heritage
Whether you'd like to spend your honeymoon in a genuine medieval castle, or visit a 5,000 year old farm -- you can do all of this in Ireland. Ireland has a history that spans different eras and many relics of those periods still survive today. If you'd like to experience a truly unique culture -- like traditional Gaelic music handed down through generations, or ancient Celtic art preserved in stunning manuscripts and gold artefacts, you'll find it all in Ireland.