The Okavango River drains the summer (January–February) rainfall from the Angola highlands and the surge flows 1,200 km (750 mi) in around one month.

The high temperature of the delta causes rapid transpiration and evaporation, resulting in three cycles of rising and falling water levels[9] that were not fully understood until the early 20th century.

The flood peaks between June and August, during Botswana's dry winter months, when the delta swells to three times its permanent size, attracting animals from kilometres around and creating one of Africa’s greatest concentrations of wildlife.

The average annual rainfall is 450 mm (18 in) (approximately one-third that of its Angolan catchment area) and most of it falls between December and March in the form of heavy afternoon thunderstorms.

December to February are hot wet months with daytime temperatures as high as 40 °C (104 °F), warm nights, and humidity levels fluctuating between 50 and 80%.

October is the most challenging month for visitors: daytime temperatures often push past 40 °C (104 °F) and the dryness is only occasionally broken by a sudden cloudburst.

[17] The Okavango Delta is both a permanent and seasonal home to a wide variety of wildlife which is now a popular tourist attraction.

[19] Other species include giraffe, blue wildebeest, plains zebra, hippopotamus,[20] impala, common eland, greater kudu, sable antelope, roan antelope, puku, lechwe, waterbuck, sitatunga, tsessebe, cheetah,[21] African wild dog, spotted hyena, black-backed jackal, caracal, serval, aardvark, aardwolf, bat-eared fox, African savanna hare, honey badger, crested porcupine, common warthog, chacma baboon, vervet monkey and Nile crocodile.

[24] Prime bird-watching areas are those with a mix of habitats such as the panhandle, the seasonal delta and the parts of the Moremi Game Reserve that are close to the water.

[32] The lechwe a bit larger than an impala, with elongated hooves and a water-repellent substance on its legs that enable rapid movement through knee-deep water.

[35] There are five important plant communities in the perennial swamp: Papyrus cyperus in the deeper waters, Miscanthus in the shallowly flooded sites, and Phragmites australis, Typha capensis and Pycreus in between.

[17] Papyrus cyperus reeds beds grow best in slow flowing waters of medium depth and are prominent at the channel sides.

Within the past 20 years many people from all over the Okavango have migrated to Maun, the late 1960s and early 1970s over 4,000 Hambukushu refugees from Angola were settled in the area around Etsha in the western Panhandle.

[40] Led by the house of Mathiba I, the leader of a Bangwato offshoot, the Batawana established complete control over the delta in the 1850s as the regional ivory trade exploded.

[41] Most Batawana, however, have traditionally lived on the edges of the delta, due to the threat that the tsetse fly poses to their cattle.

After the flooding season, the waters in the lower parts of the delta, near the base, recede, leaving moisture behind in the soil.

"[47][48] The Namibian government has presented plans to build a hydropower station in the Zambezi Region, which would regulate the Okavango's flow to some extent.

The Okavango catchment is projected to experience decreasing annual rainfall as well as increasing temperatures as a result of global warming.

[52] The effects of global warming are likely to result in reductions in the extent of floodplains in the Okavango Delta, which will have significant impacts on water availability as well as livestock rearing and agricultural activities in the region.