Mango production in the Philippines is done for full 12 months. All year round, you can find mangoes in most supermarkets. Harvesting can reach 4 times a year but most plantations makes 3 harvest on average as mangoes need 3-4 months to become fully mature.
Mango season depends on each province the fruit is grown upon. The Visayan mangoes, particularly that of from Cebu and Guimaras are the most popular variant. As a matter of fact, the Guinness Book of World Records in 1995 listed a ripe Carabao Mango variant from Guimaras as the sweetest mango in the world, and up to now has not been overthrown.
There are plenty of Mango orchards in Luzon as well particularly in Batangas and Cavite. A famous variety in Southern Tagalog is called 'kabitenyong kalabaw', which unlike others, is best eaten green than yellow. Obviously it's not sweet, and actually can compete with tamarind with its sourness.
When paired with guisadong bagoong alamang, a sour green mango can already be served as a snack or a meal, replacing your regular green garden salad. Simply writing about it makes me crave for it badly. I guess I will have to grab some later.
Green mangoes are also used by Filipinos in making one of the local's favorite dish, sinigang. The dish is usually flavored with tamarind but mangoes can be used as a replacement. Bayabas, misso or calamansi are also used in various provinces.
Green mangoes are also popular when they are dried. Compared to Cebu's dried ripe mangoes, a product for export and famous for its sweetness and are eaten as snack, dried green mangoes often serve as food additives, a soury spice or pampalasa in Tagalog. However, since dried green mangoes can be an expensive replacement for tamarind, only few markets offer it including Olivares Market in Tagaytay, Silang Market and Kadiwa Market in Dasmariñas to name a few.