For good weather and festivals, late July
Peru (Paucartambo), Fiesta de la Virgen del Carmen (religious festival with colorful costumes & strange dances), 16-18.
Tunisia, Carthage International Festival (music and dance), in Carthage’s ancient sites, Tunis, July-Aug.
Also, El-Jem International Music Festival, (orchestral), in El-Jem’s ancient colosseum.
And Festival of Malouf (traditional music), Testour.
Mongolia (Ulaan Baatar and nationwide), Naadam, a summer fair with traditional sports such as wrestling, horse racing and archery, with folk music/dance, and food.
Vanuatu (Ambrym Island), Maghe Ceremony (a traditional ceremony with Rom costume dance), July.
Bolivia (Nationwide), St. James the Apostle Feast (ritual feast with ceremonial battle), 25th
Or go for festivals only, not the weather! i.e. this is not the best season
Israel (Arad, Negev Desert), Hebrew Music Celebration, Mid-July.
Turkey (Edirne), Kirkkpinar Oiled Wrestling Championships (folk music/dancing ), 7 days. Turkey Pictures.
India (Hemis Gompa, monastery), Hemis Festival (Tibetan monks festival), June/July, 2 days
(Puri), Rath Yatra (Chariot Festival), full moon day in June/July, 1 day
(Nationwide, esp. Jodhpur), Naag Panchami (snakes & charmers+) July/Aug, 2 weeks
(Pahalgam), Amarnath Yatra (Pilgrimage to a secred mountain cave, 4days trek in July/Aug. India Pictures.
Sri Lanka (Kandy), Kandy Esala Perahera (Buddhist festival, dancers, decorated elephant parade+) 15 days in July/Aug
China (Guizhou Province), Guizhou Tribal Festivals. China Pictures.
Japan, Kyoto, Giyon Matsuri, 1-31 July, with the Yamaboko Parade (a procession of huge Hoko (two-story houses with wheels) on the 17th.
Mexico (Oaxaca), Guelaguetza (Folk dance/music/costume festival), July 21.