Lagos has a Mediterranean climate with hot, dry summers and mild, wet winters. Like the rest of the Algarve, Lagos is very sunny, averaging over 3100 hours of sunshine a year. Precipitation is concentrated in the winter months, where highs average around 16–17 °C (61–63 °F) and lows around 8–9 °C (46–48 °F), wind and humidity are also more prevalent during this season, averaging 14 km/h (8.7 mph) of wind and around 80% humidity. Summers are warm to hot, very sunny and generally still, the coastal sea breeze helps to cool down the often excessive heat of this season.
Sea temperatures have little seasonal variation and are their highest in September-October and their lowest in March, averaging 20–21 °C (68–70 °F) in the summer, and 16–17 °C (61–63 °F) in the winter.