Climate Insights for Barreiro

The climate in Barreiro is temperate. The average annual temperature is 17°C and approximately 407mm of precipitation falls per year. December is the wettest month, receiving around 59mm of rainfall. Barreiro is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: August, July, September. The coldest months are January, February, March, when temperatures can drop to 10°C.

Barreiro sees moderate temperature variation throughout the year, ranging from 10°C to 25°C. The warmest month is August, when average highs reach 25°C and the mean temperature sits around 21°C. January is the coolest month, with minimum temperatures around 10°C and an average of 12°C. Daily temperature variation is modest, with an average difference of 5°C between highs and lows. The sharpest temperature change occurs between October and November, with a 3°C shift in average temperatures.

Barreiro is a relatively dry area, receiving approximately 407mm of precipitation annually, which averages out to around 34mm per month. The wettest month is December, averaging 59mm of rainfall. October and March also tend to see above-average precipitation. The driest month is August, with just 1mm. That's 58mm less than December, 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.

Barreiro is moderately windy, with an average annual wind speed of 24km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is July, averaging 25km/h, noticeable enough to affect lighter outdoor activities. The calmest conditions occur in October, with average winds dropping to 22km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 3km/h between the calmest and windiest months. Wind tends to pick up during the summer months. The seasonal averages are 23km/h in winter, 24km/h in spring, 25km/h in summer, 22km/h in autumn.

It is currently spring in Barreiro, which began on March 20, 2026. Barreiro is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in August at around 25°C, while the coldest stretch bottoms out in January near 10°C. Summer is next, beginning on June 21, 2026 — 89 days from now.

The best time to visit Barreiro is during April, May, June, July, August, September, October and November, when the weather is most comfortable for travellers. During these months, average temperatures hover around 19°C with modest rainfall averaging 26mm per month. By contrast, January can be quite cold with temperatures dropping to 10°C. With minimal rainfall expected, you can pack light and plan outdoor activities with confidence.

The table below shows monthly climate averages for Barreiro 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.