Brasilia has a tropical savanna climate , milder due to the elevation and with two distinct seasons: the rainy season, from October to April, and the dry season, from May to September. The average temperature is 21.0 °C (69.8 °F). September, at the end of the dry season, has the highest average maximum temperature, 28.4 °C (83.1 °F), and July has major and minor lower maximum average temperature, of 25.1 °C (77.2 °F) and 12.9 °C (55.2 °F), respectively. Average temperatures from September through March are a consistent 22 °C (72 °F). With 241.5 mm (9.5 in), December is the month with the highest rainfall of the year, while June is the lowest, with only 4.9 mm (0.2 in). During the dry season, the city can have very low relative humidity levels, often below 30%.
According to Brazilian National Institute of Meteorology (INMET), the record low temperature was 1.6 °C (34.9 °F) on July 18, 1975, and the record high was 36.4 °C (97.5 °F) on October 18, 2015 and October 8, 2020. The highest accumulated rainfall in 24 hours was 132.8 mm (5.2 in) on November 15, 1963.