Monthly climate guide
Porto Velho weather in September
September in Porto Velho is typically very hot, with average daytime highs around 36°C (97°F) and night-time lows near 25°C (76°F). The month usually brings about 70 mm of rain (some rain) and is often cloudy. Daytime highs are about the same as August and 2°C warmer than October.
What stands out in September
- September sits in Porto Velho's drier season — usually a comfortable time to visit.
- Even after dark it stays around 25°C, so sleeping can feel warm.
- Porto Velho is usually about 2°C warmer than Rio Branco, 450 km away, in September.
- It's one of the drier months, with about 45% less rain than Porto Velho's average.
September is typically Porto Velho's warmest month.
Avg high
36°C
97°F
Avg low
25°C
76°F
Rainfall
70 mm
some rain
Humidity
64%
relative
Sky
62%
cloud · often cloudy
Porto Velho weather by month
Show the monthly averages as a table
| Month | Avg high | Avg low | Rain | Humidity | Cloud cover |
|---|---|---|---|---|---|
| January | 29°C / 83°F | 23°C / 74°F | 230 mm | 91% | 88% |
| February | 29°C / 83°F | 23°C / 74°F | 236 mm | 91% | 88% |
| March | 29°C / 83°F | 23°C / 74°F | 213 mm | 91% | 88% |
| April | 29°C / 83°F | 23°C / 74°F | 148 mm | 91% | 80% |
| May | 29°C / 84°F | 23°C / 73°F | 81 mm | 90% | 65% |
| June | 30°C / 86°F | 22°C / 72°F | 22 mm | 85% | 37% |
| July | 33°C / 91°F | 22°C / 72°F | 19 mm | 71% | 24% |
| August | 36°C / 96°F | 23°C / 74°F | 34 mm | 61% | 37% |
| September | 36°C / 97°F | 25°C / 76°F | 70 mm | 64% | 62% |
| October | 34°C / 93°F | 24°C / 76°F | 123 mm | 72% | 80% |
| November | 32°C / 90°F | 24°C / 76°F | 129 mm | 79% | 85% |
| December | 30°C / 86°F | 24°C / 75°F | 209 mm | 87% | 86% |
What to pack for September
- Light, breathable clothing (cotton or linen)
- A sun hat and high-SPF sunscreen
- A refillable water bottle
- An extra layer — evenings are noticeably cooler than afternoons
- A compact umbrella or packable rain jacket
- Water-resistant shoes
Is September a good time to visit Porto Velho?
Compare the months in the chart above to find your ideal window.
Best time to visit Porto Velho →Other Brazil cities in September
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Porto Velho weather in September. WeatherCompare, 2026 (NASA POWER / ERA5, 2011–2020 monthly averages). https://weathercompare.eu/weather/brazil/porto-velho/september
<a href="https://weathercompare.eu/weather/brazil/porto-velho/september">Porto Velho weather in September</a> (WeatherCompare)
<iframe src="https://weathercompare.eu/embed/brazil/porto-velho" width="300" height="160" style="border:0;border-radius:12px" loading="lazy" title="Porto Velho weather in September"></iframe> <p style="font-size:12px"><a href="https://weathercompare.eu/weather/brazil/porto-velho/september">Porto Velho weather in September</a> – WeatherCompare</p>
Porto Velho in September: quick answers
Is September a good time to visit Porto Velho?
It can be, if you like heat: September highs in Porto Velho are around 36°C. Good for the beach; plan sightseeing for early morning and evening.
How warm is Porto Velho in September?
Average highs are about 36°C (97°F) and average lows about 25°C (76°F), based on 10 years of daily data.
Does it rain a lot in Porto Velho in September?
Porto Velho typically gets around 70 mm of rain in September — some rain.
Figures are long-term averages for the area around Porto Velho (NASA POWER / ERA5, 2011–2020), not a forecast for a specific year. For upcoming days, see the live multi-source forecast.