Climate averages 1991–2020
Viamão weather
in September.
A mild, wet month: the 8th warmest and the 11th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Viamão: daytime highs average 20.8°C and nights cool to about 12.9°C. By daytime temperature it is the 8th warmest of the 12 months.
Expect about 147 mm of rain on roughly 11 days, which makes September a wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 11 h 53 min on an average September day.
The nearest other city in this atlas is Alvorada (10 km away). In September its highs average 21.5°C, 0.7°C warmer than Viamão, with 147 mm of rain.
Among the 448 cities listed in Brazil, Viamão ranks joint 428th of 448 for the warmest September highs and joint 403rd of 448 for the driest September (rainfall, lowest first). The mean September high of those 448 cities is 27.5°C; Viamão is 6.7°C cooler than that mean.
From September to October, average highs rise by 2.2°C to 23.0°C, and monthly rainfall rises from 147 mm to 170 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
Viamão climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 28.3°C20.6°C | 20.6°C | 140 | 14.2 | 13.814 h |
| February | 28.0°C20.7°C | 20.7°C | 129 | 14.0 | 13.213 h |
| March | 26.8°C19.5°C | 19.5°C | 121 | 12.6 | 12.312 h |
| April | 24.2°C16.7°C | 16.7°C | 102 | 9.6 | 11.411 h |
| May | 20.6°C13.4°C | 13.4°C | 106 | 9.2 | 10.611 h |
| June | 18.6°C11.0°C | 11.0°C | 112 | 9.4 | 10.210 h |
| July | 17.9°C10.1°C | 10.1°C | 136 | 10.1 | 10.410 h |
| August | 19.9°C11.2°C | 11.2°C | 122 | 10.3 | 11.011 h |
| September, selected | 20.8°C12.9°C | 12.9°C | 147 | 11.2 | 11.912 h |
| October | 23.0°C15.3°C | 15.3°C | 170 | 12.9 | 12.813 h |
| November | 25.0°C16.8°C | 16.8°C | 121 | 10.8 | 13.614 h |
| December | 27.4°C19.2°C | 19.2°C | 129 | 12.5 | 14.014 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
- Alvorada in SeptemberBrazil · 10 kmHigh 21.5°C · Low 12.9°C · 147 mm rain
- Gravataí in SeptemberBrazil · 16 kmHigh 21.6°C · Low 12.7°C · 147 mm rain
- Porto Alegre in SeptemberBrazil · 21 kmHigh 21.6°C · Low 12.8°C · 146 mm rain
- Canoas in SeptemberBrazil · 24 kmHigh 21.7°C · Low 12.8°C · 146 mm rain
- Guaíba in SeptemberBrazil · 29 kmHigh 21.4°C · Low 12.8°C · 146 mm rain
- São Leopoldo in SeptemberBrazil · 38 kmHigh 21.8°C · Low 12.6°C · 160 mm rain
- Novo Hamburgo in SeptemberBrazil · 46 kmHigh 21.6°C · Low 11.9°C · 160 mm rain
- Sapiranga in SeptemberBrazil · 49 kmHigh 22.3°C · Low 12.8°C · 153 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 Viamão) is explained once on the Viamão year overview and on the Sources, method and limits page.
Gravataí and Alvorada lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.