Climate Insights for Guajará Mirim

The climate in Guajará Mirim is temperate. The average annual temperature is 15°C and approximately 239mm of precipitation falls per year. December is the wettest month, receiving around 33mm of rainfall. Guajará Mirim 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 September, July, August, when temperatures can drop to 5°C.

Guajará Mirim sees moderate temperature variation throughout the year, ranging from 5°C to 20°C. January is the warmest month, though highs remain moderate at 20°C with a mean of 19°C. September is the coolest month, with minimum temperatures around 5°C and an average of 9°C. Daily temperature variation is modest, with an average difference of 3°C between highs and lows. The sharpest temperature change occurs between June and July, with a 9°C shift in average temperatures.

Guajará Mirim is a quite dry location, receiving approximately 239mm of precipitation annually, which averages out to around 20mm per month. The wettest month is January, averaging 33mm of rainfall. May and October also tend to see above-average precipitation. The driest month is September, with just 1mm. That's 32mm 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.

Guajará Mirim 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 November, averaging 13km/h, though still comfortable for most outdoor activities. The calmest conditions occur in August, with average winds dropping to 3km/h, making it an ideal period for wind-sensitive activities. Wind speeds vary significantly across the year, with a 10km/h difference between the calmest and windiest months. This level of variation is worth factoring into travel plans.

It is currently winter in Guajará Mirim, which began on June 21, 2026. Guajará Mirim 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 20°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 Guajará Mirim is during January, February, March, April, May, June, November and December, when the weather is most comfortable for travellers. During these months, average temperatures hover around 18°C with modest rainfall averaging 25mm per month. By contrast, September can be quite cold with temperatures dropping to 5°C. With minimal rainfall expected, you can pack light and plan outdoor activities with confidence.

The table below shows monthly climate averages for Guajará Mirim 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.