The best time to see wildlife in Tanzania depends on several factors, including the type of wildlife you want to see and the region you plan to visit. In general, the dry season, which runs from June to October, is considered the best time to see wildlife in Tanzania.

During the dry season, water sources become scarce, which causes animals to gather around remaining water sources. This concentration of wildlife makes it easier to spot and photograph animals on safari. Additionally, the dry season is also a popular time for wildebeest migration, where millions of wildebeest and other grazing animals move across the Serengeti and Masai Mara ecosystems in search of water and fresh grazing land.

That being said, some regions of Tanzania, such as the southern Selous Game Reserve and the western Mahale Mountains, are best visited during the wet season for optimal wildlife viewing. In these regions, the wet season coincides with the birthing season for many animals, and lush vegetation provides ample food sources, making it a prime time to see newborn animals.

Ultimately, the best time to visit Tanzania for wildlife viewing depends on your interests and preferences. It's a good idea to do some research and plan your trip around the specific regions and animals you want to see, while also taking weather conditions and seasonal patterns into account