About San Diego, Cartago Province

With a population of around 17,000, San Diego sits in Cartago Province, Costa Rica. The city operates in the America/Costa Rica time zone.

Recent weather here gives a sense of typical conditions: in 2025, San Diego recorded a mean annual temperature of 67°F, ranging from 55°F lows in December to 84°F highs in March, with about 68 inches of precipitation across the year.