If you planning to travel to Fort Constitution Historical Site, New Castle, New Hampshire, here is your 6-day travel weather forecast to make sure you have all the essentials needed during your stay. Start your day when the sunrises at 12:11 PM. The temperature feels like 25.8 with a humidity level of 74 so dress accordingly. Cloud coverage is 29 percent with visibility at 11.4 percent. Today’s UV index is 2, don’t forget the sunscreen if you need it! Today’s winds are traveling north-northwest at a speed of 3 MPH. At the end of the day don’t miss the sunset at 9:14 PM.