The oldest park and botanical garden in São Paulo, Parque da Luz, dates from 1825. When it was completed, it became popular among the city's high society, but in the 20th century, it was left to decay with the surrounding neighbourhood. Fortunately, the revitalisation of the area in the past two decades included a clean-up of the park. Delightful sculptures by notable artists were placed between the exotic trees and plants making it a joy to walk around. Although guidebooks warn about safety in the park (best visited in the mornings and not alone), I saw nothing threatening. Still, take care when visiting the park and stick to the main paths. Parque da Luz is adjacent to Pinacoteca do Estado and opposite Estação da Luz.
A nice park to walk in, hang out or enjoy one of the many events and activities that are always going on, is the Parque Agua Branca in Perdizes. Last time I was there, they had a nice handicraft fair with music.
Even without events, it's nice to walk under the tall trees and forget that you're in a big city.
Aclimação is a quiet, tranquil neighborhood surrounded by the bustling city. If you are like me, sometimes I just need to escape the noise and bustle of the chaos. Sao Paulo has many parks and green spaces, but I found myself next to Aclimação a few times.
It may not be the largest, but it does have a large pond in the center which offers shaded rest along the waterfront, with close views of the birds and water foul.
There are always people running around the lake on the paths, people walking their dogs and people sitting on the grass enjoying the serenity.
When I was in Sao Paulo, at one point I felt a bit sick. The travelling became a bit too much for me so I decided to go to a quiet place; Parque Trianon; it only took me an hour to completely recover! It is an amazing park with tropical plants where you can lie on benches. You can read a book in the shade or refresh yourself in one of the fountains.