According the Lake Victoria Climate Change Adaptation Strategy and Action Plan (2018 - 2023), in recent years, the Lake Victoria Basin (LVB) has been characterized by frequent episodes of either excessive or deficient rainfall, which has had a negative impact on the economy. In general, results indicate average annual rainfall variability of between 6 percent and 50 percent across the LVB countries for the 1981–2010 period. Annual precipitation trends for 1981–2016 for the basin show significant areas with declining rainfall. Drier periods are getting longer and more pronounced during the March–June (MAMJ) rains. Precipitation patterns for these long rains exhibit decreasing rainfall trends (20–100 millimeters per decade) over Burundi and Rwanda, northern and eastern parts of Kenya, and Uganda’s LVB region. Increased rainfall trends have also been experienced in the southern and eastern portions of the Tanzania LVB region.

Generally, it appears that rainfall will increase over the LVB in the future. However, rainfall events will become more extreme, episodic, and intense, making it difficult to capitalize on increased precipitation in most areas. Maximum daily temperatures are expected to increase 2.5°C to 3.5°C by 2050 and even by 2°C to 2.5°C by 2020 under the worst-case scenario.

Rain-fed agriculture accounts for approximately 80 percent of subsistence food production, yet it is dominated by smallholder farmers. These farmers have limited or no resources to improve their agricultural production systems, making them extremely sensitive to climatic variability. High inter-seasonal rainfall variability, reduction of arable land,
shifts in agro-ecological zones, and increasing natural resources–based conflicts can be expected in the future.

Overall vulnerability in agriculture will increase and under the most extreme emission scenario, when maximum and minimum temperatures are projected to increase by 3.5°C to 4°C, more than half of the area will become extremely vulnerable. A 1.5°C warming by the 2030s could lead to about 40 percent of present maize cropping areas being no
longer suitable for current cultivars. Under warming of less than 2°C by the 2050s, total crop production could be reduced by 10 percent. For higher levels of warming there are indications that yields may decrease by 15–20 percent across all crops and regions. Heat and drought would also result in severe losses of livestock and associated impacts
on rural communities.

Climate change–related loss of pasture and unfavorable breeding temperatures will affect livestock and fish. Current warming trends of more than +2°C above optimal levels (10–30°C) are expected to adversely affect both milk and beef production. The current warming and drying trends already have negatively affected the quantity and quality of
pastures, fodder crops and grains, water availability, and the severity and distribution of diseases and parasites.

Warmer-than-normal surface water temperatures and variability in rainfall patterns could affect fish physiological processes, thereby affecting spawning, survival of juveniles, and recruitment into the exploitable phase of population size, production, and yield.