The average annual rainfall is about  in the southwest, rising to  on the higher land of the northeast (from around Borrowdale to Glen Lorne). Very little rain typically falls during the period May to September, although sporadic showers occur most years. Rainfall varies a great deal from year to year and follows cycles of wet and dry periods from 7 to 10 years long. Records begin in October 1890 but all three Harare stations stopped reporting in early 2004.