Weather in Porto Alegre

February is the warmest month (average 25.0°C, high 29.8°C) and July is the coolest (average 14.0°C, low 9.2°C). That 11.0°C swing in monthly averages is the first thing to plan around in Porto Alegre.

Rain is rain in every month and about 1446 mm across the year. The wettest month is September at 157 mm; the driest is April at 98 mm. Porto Alegre is in Brazil at 30.0°S. The 2001–2020 NASA POWER daily record describes a mild oceanic climate. On this site the months that score closest to a 22°C day, lighter rain, and moderate humidity are April, November, and December.

When the score favours a visit

The three months with the highest comfort score are April, November, and December: April (20.9°C average, 98 mm, 80% humidity); November (20.9°C average, 110 mm, 80% humidity); December (23.1°C average, 110 mm, 79% humidity). They fall in calendar order. The score rewards averages near 22°C, lower rainfall, and humidity near 60%. It is a climate score, not a festival or price calendar.

If you prefer the hottest stretch, that is February. The coolest stretch is July.

Hot and cool months in Porto Alegre

Monthly average highs run from 18.9°C in July to 29.8°C in February. Nights follow the same curve: 9.2°C in July and 20.1°C in February.

Across the year the mean afternoon high is 24.6°C. If you want the smallest day–night shock, look at months where the high and low sit close together; February nights still hold 20.1°C.

When Porto Alegre gets wet

Rain does not take a season off. Porto Alegre receives about 1446 mm a year, and even April still sees 98 mm. September is the peak at 157 mm and 12 days with at least 1 mm.

Humidity peaks near 86%. That usually lines up with the wetter months rather than the hottest ones.

What stands out month by month

Peak heat arrives in February: 29.8°C by day, 20.1°C at night, and 77% humidity. April is the driest month, averaging only 98 mm across 11 rainy days. Highs sit near 25.9°C. May: 21.7°C high, 12.4°C low, 112 mm rain, 84% humidity.

The year bottoms out in July. Plan for 9.2°C at night and 18.9°C in the afternoon. September is the wettest month — 157 mm and 12 rainy days, with 84% humidity.

Porto Alegre and other cities in Brazil

Curitiba is about 547 km away: Porto Alegre is 3.0°C warmer than Curitiba in its hottest month and 184 mm drier over the year than Curitiba. Curitiba’s wettest month is January (221 mm) versus September here.

São Paulo is about 853 km away: Porto Alegre is 2.1°C warmer than São Paulo in its hottest month and 94 mm wetter over the year than São Paulo. São Paulo’s wettest month is January (230 mm) versus September here.

Guarulhos is about 866 km away: Porto Alegre is 1.6°C warmer than Guarulhos in its hottest month and 67 mm wetter over the year than Guarulhos. Guarulhos’s wettest month is January (228 mm) versus September here.