Climate Overview
The climate in Arroio dos Ratos is warm and mild. The average annual temperature is 19°C and approximately 1444mm of precipitation falls per year. Arroio dos Ratos receives a notable amount of rainfall throughout the year, including during its driest month. Arroio dos Ratos 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: January, February, December. The coldest months are July, June, August, when temperatures can drop to 10°C.
Temperature
Arroio dos Ratos sees moderate temperature variation throughout the year, ranging from 10°C to 30°C. The warmest month is January, when average highs reach 30°C and the mean temperature sits around 25°C. July is the coolest month, with minimum temperatures around 10°C and an average of 14°C. On average, daily temperatures fluctuate by about 9°C between overnight lows and afternoon highs. The sharpest temperature change occurs between April and May, with a 4°C shift in average temperatures.
Precipitation
Arroio dos Ratos is a fairly wet location, receiving approximately 1444mm of precipitation annually, which averages out to around 120mm per month. The wettest month is September, averaging 170mm of rainfall. May and October also tend to see above-average precipitation. The driest month is April, with just 88mm. That's 82mm less than September, the wettest month. Rainfall is relatively evenly distributed throughout the year, so there is no pronounced dry or wet season to plan around.
Wind
Arroio dos Ratos is mildly breezy, with an average annual wind speed of 15km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is October, averaging 17km/h, though still comfortable for most outdoor activities. The calmest conditions occur in June, with average winds dropping to 13km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 4km/h between the calmest and windiest months. Wind tends to pick up during the summer months. The seasonal averages are 14km/h in winter, 17km/h in spring, 16km/h in summer, 14km/h in autumn.
Seasons
89 days until Winter
It is currently autumn in Arroio dos Ratos, which began on March 20, 2026. Arroio dos Ratos 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 January at around 30°C, while the coldest stretch bottoms out in July near 10°C. Winter is next, beginning on June 21, 2026 — 89 days from now.
Spring
Temperatures range from 13 to 26°C. Rainfall is heavy, totalling around 442mm across the season with a monthly average of 147mm. Winds are moderate at around 17km/h. An umbrella or waterproof jacket is advisable as spring showers are frequent.
Summer
Temperatures range from 18 to 30°C. Rainfall is heavy, totalling around 303mm across the season with a monthly average of 101mm. Winds are moderate at around 16km/h. Light, breathable clothing is ideal — perfect conditions for outdoor activities.
Autumn
Temperatures range from 13 to 28°C. Rainfall is heavy, totalling around 375mm across the season with a monthly average of 125mm. Winds are generally light, averaging 14km/h. A waterproof jacket and sturdy footwear are recommended as rain becomes more frequent.
Winter
Temperatures range from 10 to 20°C. Rainfall is heavy, totalling around 323mm across the season with a monthly average of 108mm. Winds are generally light, averaging 14km/h. A light jacket or sweater is usually sufficient, though cooler evenings may call for an extra layer.
Best Time to Visit
The best time to visit Arroio dos Ratos is during February, April and August, when the weather is most comfortable for travellers. During these months, average temperatures hover around 20°C with modest rainfall averaging 92mm per month. By contrast, January can be uncomfortably hot with highs reaching 30°C, while July is the coldest period with lows dropping to 10°C. Despite being the best months overall, some rain is still likely — pack a waterproof layer and plan a mix of indoor and outdoor activities.
Monthly Climate Data
The table below shows monthly climate averages for Arroio dos Ratos 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.