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 11:46 AM. The temperature feels like 36.4 with a humidity level of 61 so dress accordingly. Cloud coverage is 9 percent with visibility at 14.5 percent. Today’s UV index is 2, don’t forget the sunscreen if you need it! Today’s winds are traveling west-northwest at a speed of 9 MPH. At the end of the day don’t miss the sunset at 9:10 PM.