Rio Grande do Sul weather in September
September is one of the least pleasant months in Rio Grande do Sul: highs of 22°C (71°F) and about 157 mm (6.2 in) of rain on average. Nights average 12°C (53°F) and cloud cover 62% (NASA POWER, 2001–2025 averages). It is the wettest month of the year and the 5th coolest. Compared with August, it is warmer and wetter; October brings highs of 24°C (75°F) and 155 mm (6.1 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 September a good time to visit Rio Grande do Sul?
least pleasant month Weather score 61/100.
September is one of the least pleasant months for weather in Rio Grande do Sul. For better conditions, consider Feb–May, Aug, Nov–Dec.
Does it rain a lot in Rio Grande do Sul in September?
Yes, it is one of the rainy months: about 157 mm (6.2 in) falls in an average September. It is the wettest month of the year.
How warm is Rio Grande do Sul in September?
Days average 22°C (71°F) and nights 12°C (53°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 September
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 | 22°C (71°F) | 12°C (53°F) | 157 mm | least pleasant |
| Caxias do Sul | 20°C (69°F) | 10°C (50°F) | 166 mm | fair |
| Pelotas | 19°C (66°F) | 11°C (51°F) | 134 mm | least pleasant |
| Santa Maria | 22°C (71°F) | 10°C (50°F) | 156 mm | fair |
| Gravataí | 22°C (71°F) | 12°C (53°F) | 157 mm | least pleasant |
| Passo Fundo | 22°C (71°F) | 10°C (50°F) | 160 mm | fair |
| São Leopoldo | 22°C (71°F) | 12°C (53°F) | 157 mm | least pleasant |
| Rio Grande | 17°C (63°F) | 14°C (56°F) | 131 mm | least pleasant |
| Alvorada | 22°C (71°F) | 12°C (53°F) | 157 mm | least pleasant |