Climate and Weather in central Chile. The weather in central Chile is typical of a Mediterranean climate. Summers are warm and winters are much cooler and wetter. The average high temperature during summer in Santiago is 20°C (68°F), while winter lows between June and July drop to 8°C (46°F).limate and Weather in central Chile. The weather in central Chile is typical of a Mediterranean climate. Summers are warm and winters are much cooler and wetter. The average high temperature during summer in Santiago is 20°C (68°F), while winter lows between June and July drop to 8°C (46°F).