These are Wind Pattern Maps for Central Park, from Volume VIII of a "Regional Survey of New York and its Environs" part of the 1929 New York Regional Plan by Harold M. Lewis et al. They are provided for people wanting to fly kites and balloons along the Gowanus Canal. Please note that because of the bowl shape of the Gowanus valley, monarch butterflies have been observed flying towards the northwest, but then veering southwest because of local wind patterns.