The park is situated in the dry semi-arid climatic region and rain is received mainly during the northeast monsoon.

Yala hosts a variety of ecosystems ranging from moist monsoon forests to freshwater and marine wetlands.

The 2004 Indian Ocean tsunami caused severe damage on the Yala National Park and 250 people died in its vicinity.

In 1560 Spanish cartographer Cipriano Sánchez noted Yala in his map "is abandoned for 300 years due to insalubrious conditions.

"[1] Chief Justice Sir Alexander Johnston wrote a detailed account on Yala in 1806 after travelling from Trincomalee to Hambantota.

[2] Initially the extent of the reserve was 389 square kilometres (150 sq mi) between the Menik and Kumbukkan Rivers.

The forest area between Palatupana and Yala was declared a hunting site reserved only for the resident sportsmen.

On 1 March 1938, Yala became a national park when the Flora and Fauna Protection Ordinance was passed into law by D. S. Senanayake, the minister of agriculture.

The national park is situated in the dry semi-arid climatic region and rain is received mainly during the northeast monsoon.

The bodies of surface water appear in the forms of streams, tanks, waterholes, rock pools, and lagoons.

[2] Many rivers and streams flow in a southeasterly direction, originating in the highlands of adjacent Uva and central hills.

[2] Yala lay in the direct path of the 2004 Indian Ocean tsunami, which impacted Sri Lanka 90 minutes after its generation.

The satellite images revealed that mean normalized difference vegetation index (NDVI) range from 0.245 to 0.772 in the Block I and II.

The study found out that their movements were consistent with behaviour prompted by immediate cues generated by the tsunami waves rather than a response to a "sixth sense".

Other habitat types of the Block I are tanks and water holes, lagoons and mangroves and chena lands.

The mangroves of Block II occur around the estuary of Menik River, which extend to 100 hectares (0.39 sq mi).

Among 300 odd floral species are Manilkara hexandra, Drypetes sepiaria, Ceylon satinwood, Terminalia arjuna, limonia, Berrya cordifolia, Randia dumetorum, Pleurostylia opposita, Gymnema sylvestre, bell mimosa, neem, banyan, toothbrush tree, Schleichera oleosa, Vitex pinnata, Indian blackberry, Gmelina asiatica, Carissa spinarum, Euphorbia antiquorum, and Acacia eburnea.

Rock pigeon, barred buttonquail, Indian peafowl, black stork, black-winged stilt, and greater flamingo are among the other bird species.

[9] Including Sri Lankan elephant, 44 species of mammals are resident in Yala National Park,[2] and it has one of the highest leopard densities in the world.

[13] The Sri Lankan sloth bear, leopard, elephant, and wild water buffalo are all threatened mammals that Yala harbours.

Toque macaque, golden palm civet, red slender loris, and fishing cat are among the other mammals that can be seen in Yala.

[9] There are 18 amphibian species that have been recorded from Yala, while Bufo atukoralei and Adenomus kelaartii are endemic to Sri Lanka.

[citation needed] Seafaring traders brought Indo-Aryan civilisation with them, as Yala is situated in their trading route.

A large number of ancient although disrepaired tanks are the evidence of a rich hydraulic and agricultural civilisation dating back to 5th century BC.

[15] Poaching, gem-mining, logging, encroachment by agriculture, and free-roaming domestic livestock are the main threats to the park.

In Blocks III and IV, the encroachment is severe as chena cultivation and burning, to provide grazing in the dry season, collides with the boundary.

The growth of invasive alien species such as Lantana camara, Opuntia dillenii, Chromolaena odorata is threatening the native plants.

A 40 kilometres (25 mi) long electric fence was erected to prevent elephants from moving into nearby villages.

Note that the Situlpahuwa pilgrimage site, geographically in Block III, has kind of an 'enclave' status and is accessible FOC through separate roads from Tissa and Kataragama.

Since the end of the civil war, May 2009, no violence has occurred in Yala area also and it is fully safe for visitors; this was also the main factor in opening blocks III and V for tourists.