Every year we attend the taping for one of the "live" concerts they show on the 4th. A couple years ago the "live" concert was being taped the week before. It's an outdoors thing.

It was cold, low 50's, windy, and a bit rainy, some people were literally wearing mittens because it was a damp chilling evening. A week later on the 4th it was in the 90's and I'm sure people all over the country were wondering why the people in New york at the "live" concert were wearing sweaters and the rest, while the people just a few blocks away watching the fireworks were obviously dying of the heat.

You can't predict what the first week of July will be like, even a few days before. I say go for it, I'm in the city every day, and I think it's great in the summer. It's a great time to visit, the city isn't full of the tourists that come over in August, the weather is generally better, and the fireworks are fantastic.