 Gaborone has been affected by three floods based on records going back to 1995, one in 2000, one in 2001 that caused an estimated 5,000,000 Botswana pula worth of damage, and one in 2006.The highest humidity occurs in June at 90% while the lowest humidity is in September at 28%.Solar irradiance ranges from 4.1 kWh/m2/day in June to 7.3 kWh/m2/day in December.