Rio Branco Weather in September
Average highs run from 34°C on September 1 to 34°C on September 30, and lows from 22°C to 23°C. Normal precipitation for the month is 75 mm over about 12 wet days.
September day by day
The normal high and low for each date, in °C.
- Normal low
- Normal high
- Reanalysis extreme high
- Reanalysis extreme low
September at a glance
- Average high
- 34°C
- Average low
- 23°C
- Precipitation
- 75 mm
- Reanalysis high
- 40°CSep 25, 2005
- Reanalysis low
- 14°CSep 21, 1995
- Daylight
- 11 h 55 min to 12 h 11 min
- Cloud cover
- 63%
- Humidity
- 67%
- Dew point
- 20°C
- Wind
- 2.9 km/h
Every day of the month
A wet day has at least 1 mm of precipitation in the reanalysis.
| Date | Normal high | Normal low | Reanalysis high | Reanalysis low | Chance wet |
|---|---|---|---|---|---|
| Sep 1 | 34°C | 22°C | 39°C 1998 | 19°C 2008 | 32% |
| Sep 2 | 34°C | 22°C | 38°C 1998 | 19°C 2011 | 34% |
| Sep 3 | 34°C | 22°C | 38°C 1998 | 18°C 2005 | 35% |
| Sep 4 | 34°C | 22°C | 39°C 1997 | 19°C 2018 | 36% |
| Sep 5 | 34°C | 22°C | 39°C 1997 | 16°C 2018 | 36% |
| Sep 6 | 34°C | 22°C | 38°C 1997 | 17°C 2018 | 36% |
| Sep 7 | 34°C | 22°C | 39°C 1997 | 18°C 1996 | 37% |
| Sep 8 | 34°C | 22°C | 40°C 1998 | 20°C 2010 | 38% |
| Sep 9 | 34°C | 22°C | 39°C 1997 | 20°C 1991 | 38% |
| Sep 10 | 34°C | 22°C | 39°C 1997 | 16°C 2003 | 37% |
| Sep 11 | 35°C | 23°C | 39°C 2018 | 14°C 2003 | 37% |
| Sep 12 | 35°C | 23°C | 39°C 2018 | 15°C 2003 | 37% |
| Sep 13 | 35°C | 23°C | 39°C 1998 | 17°C 2004 | 38% |
| Sep 14 | 35°C | 23°C | 38°C 1995 | 16°C 2004 | 39% |
| Sep 15 | 34°C | 23°C | 38°C 2015 | 18°C 2004 | 40% |
| Sep 16 | 34°C | 23°C | 39°C 2019 | 18°C 1999 | 41% |
| Sep 17 | 34°C | 23°C | 38°C 2015 | 18°C 1999 | 41% |
| Sep 18 | 34°C | 23°C | 39°C 1998 | 18°C 2001 | 42% |
| Sep 19 | 34°C | 23°C | 39°C 1997 | 20°C 2001 | 43% |
| Sep 20 | 34°C | 23°C | 39°C 1997 | 17°C 1995 | 44% |
| Sep 21 | 34°C | 23°C | 39°C 2005 | 14°C 1995 | 45% |
| Sep 22 | 34°C | 23°C | 39°C 2005 | 17°C 1998 | 45% |
| Sep 23 | 34°C | 23°C | 39°C 2005 | 19°C 1998 | 44% |
| Sep 24 | 34°C | 23°C | 40°C 2005 | 19°C 2013 | 44% |
| Sep 25 | 34°C | 23°C | 40°C 2005 | 18°C 2013 | 45% |
| Sep 26 | 34°C | 23°C | 38°C 2010 | 16°C 2007 | 48% |
| Sep 27 | 34°C | 23°C | 39°C 1998 | 17°C 2000 | 49% |
| Sep 28 | 34°C | 23°C | 39°C 2010 | 18°C 2000 | 49% |
| Sep 29 | 34°C | 23°C | 39°C 2010 | 20°C 2000 | 50% |
| Sep 30 | 34°C | 23°C | 39°C 2010 | 20°C 2003 | 50% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (GMT-5).
- September 1
- sunrise 5:34 AM, sunset 5:29 PM
- September 30
- sunrise 5:16 AM, sunset 5:27 PM
Other months
Sources
Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.