I did it the past two years, taking a break this year from going from one marathon to the next. 2014 was 38 degrees with insane (40 mph?) wind, and I ran a fantastic first marathon (3:34). Last year was 60, humid, overcast and not windy, and I just had no desire to do it at all (3:48 or something. I don't even know!). If there is wind, there are so many people running that it's easy to draft. The worst wind will be on the Verrazano, and that's when you're fresh. I live in NYC and am very familiar with the course. Perhaps too familiar. I think it's a great idea to have a handle of what you're getting into, but there are so many intricacies and nuances, you can't overthink it. It's not like Boston where you know where the worst part is, or a race like New Jersey that is a selightfully flat. I have not negative split in a marathon, and I honestly don't think that NYC is a course that would allow for most of its runners to do so. I personally think that it's harder than Boston is (and I ran Boston this year, with the heat).
Here's a little insight: The entire stretch of Lafayette Ave (mile 8) is a steady, long incline. It doesn't look like much, but it will tire you out if you're not careful. Then in leading up to the Queensborough, the stretch up Manhattan ave is again, a long steady incline followed by a decent haul over the Pulaski bridge at the half. Queensborough is what it is. Annoying. Quiet. If you've done your strength training, it will still hurt, but you'll survive. Use it to take time to fuel. Don't pay attention to your watch, it'll go wonky. First ave is a delightful, energy-filled, downhill gift. But bank some speed and save yourself for the crossing over the 138 st bridge, around mile 18-19. Central Park isn't too bad- more rolling hills than anything else, but if you didn't run smart, they will wear you down so late in the game. I agree with the poster who said that the lead-in to Central Park, as you're running down 5th ave from the Harlem, is not pleasant at mile 23. In 2014, the wind was coming from the northwest-ish, and literally slammed into my side as I was attempting to run up that incline. It was probably the hardest thing I have ever done in a race. However, that was then, I survived, and my job here is not to freak you out. Once you get into the park, the crowds are nuts, and it's beautiful with the foliage and all of the banners. The finish is one of the nicest downhills in the park. It's insanely exciting and one of the best NYC experiences you could ever have, native dweller or not. Run smart, listen to your body, and just take it all in. I am getting goosebumps just writing about it.