There’s plenty to enjoy in Middle Chile all year round as the area enjoys a Mediterranean-style climate. 
If you want to enjoy the beaches, it’s best to go in summer (December to February). However bear in mind that Viña del Mar is particularly busy during this period, especially on New Year’s Eve, which is a spectacular occasion in Viña del Mar and Valparaíso. The Viña del Mar festival also takes place during February and attracts thousands of tourists. 
If you want to go camping and hiking, it’s best to go in autumn (March to May) or spring (September to November), as the temperatures are warm and pleasant. 
March is harvest time in the vineyards and is a good time to take a wine tour.  
To make the most of the ski season, go in the winter, from July to mid-September.