In the low wind season (May to August) you find 15-25 knots. I would say about 70% of the time you find that wind, and another 30% you find 9-14 knots. It can be quite gusty - even sometimes dangerous because it speeds up very fast and gets unpredictable strong (that wind is called Paraca).
It's the peninsula of Paracas. 250km south of Lima, 35min (30km) south of Pisco, direction towards Laguna Grande, after the Salinas de Otuma. You will need your own transportation to get into the reserve after you arrive to Paracas.