In the airport area of Pudahuel, mean rainfall is per year, about 80% of which occurs during the winter months (May to September), varying between of rainfall during these months. That amount contrasts with a very sunny season during the summer months between December and March, when rainfall does not exceed on average, caused by an anticyclonic dominance continued for about seven or eight months. There is significant variation within the city, with rainfall at the lower-elevation Pudahuel site near the airport being about 20 percent lower than at the older Quinta Normal site near the city centre.