About San Diego, Cartago Province's Climate & Weather History

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.

In 2025, San Diego recorded an average annual temperature of 67°F. The hottest temperatures reached 84°F in March; the coolest were 55°F in December. Total precipitation for the year was 68 inches, with the wettest month being October.