Zambia's location near the equator gives the country its tropical climate. The annual rainfall in Zambia averages between 700 mm in the south and 1,400 mm in the north. The hot months are very dry, receiving almost no rainfall between May and August. The wet season (September-April) rainfall is controlled by the passage of the tropical rain belt (also known as the Inter‐Tropical Conversion Zone, ITCZ) which oscillates between the northern and southern tropics over the course of a year, bringing rain between October and April of 150‐300 mm per month. Variations in the movements of the ITCZ can cause large variations in the rainfall received from one year to the next. Rainfall in Zambia is also strongly influenced by the El Niño Southern Oscillation (ENSO), which causes further inter‐annual variability. El Niño conditions (warm phase) bring drier than average conditions in the wet summer months (December-February) in the southern half of the country, whilst the north of the country simultaneously experiences significantly wetter‐than average conditions. The reverse pattern occurs with La Niña (cold phase) episodes, with dry conditions in the north and wet conditions in the south. Key historical climate trends are summarized below:

Temperature

• Mean annual temperature has increased by 1.3°C since 1960, an average rate of 0.29°C per decade. The rate of increase is most rapid in the winter, at 0.34°C per decade.
• Daily temperature observations show significantly increasing trends in the frequency hot days and nights in all seasons.
• The average number of ‘hot’ days per year in Zambia has increased by 43 (an additional 11.8% of days) between 1960 and 2003.
• The frequency of cold days and nights has decreased since 1960 in all seasons and the average number of ‘cold ‘days per year has decreased by 22 (6% of days) between 1960 and 2003.

Precipitation

• Mean annual rainfall over Zambia has decreased by an average rate of 1.9 mm per month (2.3%) per decade since 1960. This annual decrease is largely due to decreases in December-February rainfall (or part of the wet season), which has decreased by 7.1 mm per month (3.5%) per decade.
• Daily precipitation observations show some indication of reductions in the contribution of heavy events to total rainfall, and the magnitude of maximum 1‐ and 5‐day rainfalls, but none of these trends are statistically significant.

This section provides the options to visualize historical climate data for different timeframes via map and annual cycle chart.