Climate Insights for São Sebastião do Caí

The climate in São Sebastião do Caí is temperate. The average annual temperature is 14°C and approximately 302mm of precipitation falls per year. July is the wettest month, receiving around 33mm of rainfall. São Sebastião do Caí is in the Southern Hemisphere. The seasons are reversed: summer runs from December to February, while winter falls between June and August. The summer months are: June, January, May. The coldest months are September, August, October, when temperatures can drop to 5°C.

São Sebastião do Caí sees moderate temperature variation throughout the year, ranging from 5°C to 17°C. June is the warmest month, though highs remain moderate at 17°C with a mean of 16°C. September is the coolest month, with minimum temperatures around 5°C and an average of 10°C. Daily temperature variation is modest, with an average difference of 3°C between highs and lows. The sharpest temperature change occurs between July and August, with a 5°C shift in average temperatures.

São Sebastião do Caí is a quite dry location, receiving approximately 302mm of precipitation annually, which averages out to around 25mm per month. The wettest month is January, averaging 33mm of rainfall. February and March also tend to see above-average precipitation. The driest month is September, with just 2mm. That's 31mm less than January, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic.

São Sebastião do Caí is relatively calm, with an average annual wind speed of 8km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is May, averaging 13km/h, though still comfortable for most outdoor activities. The calmest conditions occur in August, with average winds dropping to 2km/h, making it an ideal period for wind-sensitive activities. Wind speeds vary significantly across the year, with a 11km/h difference between the calmest and windiest months. This level of variation is worth factoring into travel plans. Wind tends to pick up during the summer months. The seasonal averages are 6km/h in winter, 5km/h in spring, 9km/h in summer, 10km/h in autumn.

It is currently winter in São Sebastião do Caí, which began on June 21, 2026. São Sebastião do Caí is in the Southern Hemisphere, where the seasons are reversed: spring starts in September, summer in December, autumn in March, and winter in June. The warmest period peaks in June at around 17°C, while the coldest stretch bottoms out in September near 5°C. Spring is next, beginning on September 23, 2026 (16 days from now).

The best time to visit São Sebastião do Caí is during February, May, June and July, when the weather is most comfortable for travellers. During these months, average temperatures hover around 16°C with modest rainfall averaging 33mm per month. By contrast, September can be quite cold with temperatures dropping to 5°C. A light rain jacket is recommended, though showers are generally brief and shouldn't disrupt your plans.

The table below shows monthly climate averages for São Sebastião do Caí based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.