It gets hot and humid in New York in the Summer. August is especially humid. Central Park tends to be the coolest spot in Manhattan during the Summer, though, because the grass and trees cool things down. You will see more butterflies in the Park towards the end of the Summer, because that is when the plants that attract them are blooming.
There are plenty of ceremony locations in Central Park that offer some shade from the sun. The Ladies’ Pavilion offers a little shade for smaller groups and is by the Lake so any breeze over the water may keep you cool. The section of the Lake right by the Ladies’ Pavilion is home to many turtles and they can be seen sunning themselves by the bank during the Summer. Cop Cot has a roof of leaves in the Summertime that will provide some shade on a hot day and will fit a larger group.
The Shakespeare Garden is lovely in the Summer. It is planted with flowers that would have been popular in England during Shakespeare’s time, hence the name, and they are in flower during the Summer. The garden is shaded in parts and there is a lovely, big stone seat at the top of the garden, which is in shade, and always a cool spot to sit on and cool down.
It might be nice to row a boat on the Lake to enjoy some sunshine in the Summer time. Row boats can be rented from the Loeb Boathouse between 10am and 5:30pm every day. They cost $12 for the first hour. During summer months, the Carousel is open seven days a week if the weather is good, that is a great spot for a more unusual wedding photograph.
Sunset weddings are popular in Central Park during the Summer. A ceremony at around 7pm would be lovely with the sun setting behind you. For more information on sunset times, check the Central Park weather part of my website.