Climate averages 1991–2020
Viamão weather
in December.
A warm, wet month: the 3rd warmest and the joint 7th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
December is a warm month in Viamão: daytime highs average 27.4°C and nights cool to about 19.2°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 129 mm of rain on roughly 13 days, which makes December a wet month (the joint 7th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 02 min on an average December day.
The nearest other city in this atlas is Alvorada (10 km away). In December its highs average 28.1°C, 0.7°C warmer than Viamão, with 129 mm of rain.
Among the 448 cities listed in Brazil, Viamão ranks joint 287th of 448 for the warmest December highs and joint 117th of 448 for the driest December (rainfall, lowest first). The mean December high of those 448 cities is 28.5°C; Viamão is 1.1°C cooler than that mean.
From December to January, average highs rise by 0.9°C to 28.3°C, and monthly rainfall rises from 129 mm to 140 mm.
The annual picture
December 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 | 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, selected | 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
December in nearby cities
- Alvorada in DecemberBrazil · 10 kmHigh 28.1°C · Low 19.3°C · 129 mm rain
- Gravataí in DecemberBrazil · 16 kmHigh 28.1°C · Low 18.9°C · 129 mm rain
- Porto Alegre in DecemberBrazil · 21 kmHigh 28.4°C · Low 19.2°C · 124 mm rain
- Canoas in DecemberBrazil · 24 kmHigh 28.4°C · Low 19.1°C · 124 mm rain
- Guaíba in DecemberBrazil · 29 kmHigh 28.4°C · Low 19.3°C · 124 mm rain
- São Leopoldo in DecemberBrazil · 38 kmHigh 28.2°C · Low 18.8°C · 145 mm rain
- Novo Hamburgo in DecemberBrazil · 46 kmHigh 27.9°C · Low 18.1°C · 145 mm rain
- Sapiranga in DecemberBrazil · 49 kmHigh 28.3°C · Low 18.6°C · 141 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.