Rio Grande do Sul weather in December
December is one of the best months to visit Rio Grande do Sul: highs of 28°C (83°F) and about 110 mm (4.3 in) of rain on average. Nights average 18°C (64°F) and cloud cover 55% (NASA POWER, 2001–2025 averages). It is the 4th driest month of the year and the 4th warmest. Compared with November, it is warmer and about as wet; January brings highs of 29°C (85°F) and 120 mm (4.7 in) of rain.
Figures are long-term averages for Porto Alegre, the largest city in Rio Grande do Sul. See below for other places.
Is December a good time to visit Rio Grande do Sul?
best month Weather score 71/100.
Yes. December is one of the best months for weather in Rio Grande do Sul.
Does it rain a lot in Rio Grande do Sul in December?
Some rain is normal: about 110 mm (4.3 in) falls in an average December. It is the 4th driest month of the year.
How warm is Rio Grande do Sul in December?
Days average 28°C (83°F) and nights 18°C (64°F).
Rio Grande do Sul weather by month
| Month | High | Low | Rain | Cloud | Weather |
|---|---|---|---|---|---|
| January | 29°C (85°F) | 20°C (67°F) | 120 mm | 58% | fair |
| February | 30°C (85°F) | 20°C (68°F) | 103 mm | 55% | best |
| March | 28°C (83°F) | 18°C (65°F) | 103 mm | 56% | best |
| April | 26°C (78°F) | 16°C (60°F) | 98 mm | 56% | best |
| May | 21°C (70°F) | 12°C (54°F) | 112 mm | 60% | best |
| June | 19°C (66°F) | 10°C (50°F) | 113 mm | 62% | fair |
| July | 18°C (65°F) | 9°C (48°F) | 149 mm | 58% | least pleasant |
| August | 20°C (69°F) | 10°C (50°F) | 116 mm | 56% | best |
| September | 22°C (71°F) | 12°C (53°F) | 157 mm | 62% | least pleasant |
| October | 24°C (75°F) | 14°C (57°F) | 155 mm | 63% | least pleasant |
| November | 26°C (79°F) | 16°C (60°F) | 110 mm | 54% | best |
| December | 28°C (83°F) | 18°C (64°F) | 110 mm | 55% | best |
Sources: 2001–2025 monthly averages from NASA POWER (MERRA-2 reanalysis). Page updated . How we rate months
Weather across Rio Grande do Sul in December
Weather can differ a lot within Rio Grande do Sul: coasts, hills and mountains each have their own climate.
| Place | High | Low | Rain | Weather |
|---|---|---|---|---|
| Porto Alegre | 28°C (83°F) | 18°C (64°F) | 110 mm | best |
| Caxias do Sul | 26°C (79°F) | 16°C (60°F) | 134 mm | best |
| Pelotas | 27°C (81°F) | 17°C (63°F) | 93 mm | best |
| Canoas | 28°C (83°F) | 18°C (64°F) | 110 mm | best |
| Santa Maria | 29°C (84°F) | 16°C (62°F) | 153 mm | fair |
| Gravataí | 28°C (83°F) | 18°C (64°F) | 110 mm | best |
| Novo Hamburgo | 28°C (82°F) | 17°C (63°F) | 122 mm | best |
| Viamão | 28°C (83°F) | 18°C (64°F) | 110 mm | best |
| Passo Fundo | 27°C (81°F) | 16°C (61°F) | 150 mm | fair |
| São Leopoldo | 28°C (83°F) | 18°C (64°F) | 110 mm | best |
| Rio Grande | 24°C (75°F) | 20°C (68°F) | 91 mm | best |
| Alvorada | 28°C (83°F) | 18°C (64°F) | 110 mm | best |