Climate averages 1991–2020
Ariquemes weather
in September.
A hot, moderately wet month: the 2nd warmest and the 4th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a hot month in Ariquemes: daytime highs average 33.1°C and nights cool to about 23.3°C. By daytime temperature it is the 2nd warmest of the 12 months.
Expect about 86 mm of rain on roughly 14 days, which makes September a moderately wet month (the 4th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 02 min on an average September day.
The nearest other city in this atlas is Porto Velho (159 km away). In September its highs average 32.6°C, 0.6°C cooler than Ariquemes, with 103 mm of rain.
Among the 448 cities listed in Brazil, Ariquemes ranks joint 46th of 448 for the warmest September highs and joint 312th of 448 for the driest September (rainfall, lowest first). The mean September high of those 448 cities is 27.5°C; Ariquemes is 5.6°C warmer than that mean.
From September to October, average highs fall by 1.1°C to 32.1°C, and monthly rainfall rises from 86 mm to 142 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Ariquemes climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 29.5°C22.8°C | 22.8°C | 281 | 27.6 | 12.613 h |
| February | 29.3°C22.7°C | 22.7°C | 282 | 26.3 | 12.412 h |
| March | 29.4°C22.8°C | 22.8°C | 274 | 28.1 | 12.212 h |
| April | 29.4°C22.7°C | 22.7°C | 185 | 23.8 | 11.912 h |
| May | 29.3°C22.2°C | 22.2°C | 91 | 15.7 | 11.712 h |
| June | 30.7°C21.5°C | 21.5°C | 20 | 4.4 | 11.612 h |
| July | 32.7°C21.5°C | 21.5°C | 13 | 2.5 | 11.612 h |
| August | 33.9°C22.4°C | 22.4°C | 32 | 5.3 | 11.812 h |
| September, selected | 33.1°C23.3°C | 23.3°C | 86 | 13.9 | 12.012 h |
| October | 32.1°C23.3°C | 23.3°C | 142 | 20.1 | 12.312 h |
| November | 30.4°C23.1°C | 23.1°C | 208 | 23.2 | 12.613 h |
| December | 29.8°C22.9°C | 22.9°C | 246 | 26.8 | 12.713 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Porto Velho in SeptemberBrazil · 159 kmHigh 32.6°C · Low 23.8°C · 103 mm rain
- Ji Paraná in SeptemberBrazil · 161 kmHigh 33.3°C · Low 23.2°C · 80 mm rain
- Cacoal in SeptemberBrazil · 243 kmHigh 33.3°C · Low 23.0°C · 90 mm rain
- Riberalta in SeptemberBolivia · 351 kmHigh 32.2°C · Low 23.1°C · 84 mm rain
- Vilhena in SeptemberBrazil · 445 kmHigh 30.8°C · Low 20.9°C · 84 mm rain
- Rio Branco in SeptemberBrazil · 522 kmHigh 32.4°C · Low 22.7°C · 76 mm rain
- Trinidad in SeptemberBolivia · 583 kmHigh 31.2°C · Low 22.2°C · 106 mm rain
- Coari in SeptemberBrazil · 648 kmHigh 30.2°C · Low 24.6°C · 123 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Ariquemes) is explained once on the Ariquemes year overview and on the Sources, method and limits page.