Originally Posted by weatherguy
What's a good blue fabric that allows a blazer to be suitable for day and evening wear?
For both day and evening in the spring and summer and all around use I would go with a 100% tropical weight wool with a very fine twill. For a less formal look, go with patch pockets and brown horn buttons. Also less formal is more dark blue and avoid mid-night blue.
I would't go worsted unless you were looking for a year round blazer. But then it will be warmer in the summer. I would go for the lightweight and then try and budget for another one in a heavier worsted for fall and winter, maybe with different features like flap pockets and different buttons for variety. Most guys, over time, end up with several blue jackets/blazers. They are very versatile.