Soundproofing casement windows
It might help, if that is where most of the sound is coming through. Newer windows have varying sound-transmission ratings (the more you spend, the better they are at blocking noise, generally). If you have old single-pane windows... it might not help much because the sound is coming through the whole thing.
I had a room where I needed to sleep in the day but the windows were old single-pane units. I had to place thick foam panels against them, tightly, when I was sleeping.