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 9:39 AM. The temperature feels like 55.05 with a humidity level of 56 so dress accordingly. Cloud coverage is 9 percent with visibility at 13.3 percent. Today’s UV index is 8, don’t forget the sunscreen if you need it! Today’s winds are traveling west-northwest at a speed of 6 MPH. At the end of the day don’t miss the sunset at 11:41 PM.