The Northern Territory's climate is distinctly different from that of southern Australia, and varies greatly between the northern part, known as the 'Top End' and the southern extremities. There are two distinct seasons: the 'wet' (October to April) and the 'dry' (May to September). Alice Springs’ climate is one of extremes with hot summers and cold winters when night time temperatures can fall below zero. Rainfall varies dramatically from year to year, but the annual average is around 286 millimetres. Daytime summer temperatures are generally in the high 30s, with dry, cool nights. Spring can bring thunderstorms, hail and dust storms.