Durban is characterised by a mild subtropical climate with warm wet summers and mild moist to dry winters, which are frost-free. However, due to large altitude variations, some western suburbs get very cold in the winter. Durban has an annual rainfall of 1,009 millimetres (39.7 in) The average annual temperature is 210C, with daytime maxima peaking from January to March at 28 °C (82 °F) and the minimum is 21 °C (70 °F), dropping to daytime highs from June to August of 23 °C (73 °F) and the minimum is 11 °C (52 °F). Sunrise in Durban is at 04h45 *(04h15) and sunset is 19h00 *(19h30) in summer & rise at 06h30 *(06h10) and set at 17h20 *(17h00) in winter. (* = dawn and dusk) The metropolitan area is topographically hilly, with very few flat areas, except in the immediate vicinity of the central business district and the harbour. The western suburbs off Hillcrest and Kloof are significantly higher above sea-level, reaching up to 850 metres (2,789 ft) in the community of Botha's Hill. Many gorges and ravines are found within the metropolitan area. There is almost no true coastal plain.