December weather forecast
Porto Alegre, Brazil

December showcases the height of summer in Porto Alegre with warm weather, a high temperature nearing 29.8°C (85.6°F), and substantial rainfall of 60mm (2.36"). The onset of summer adorns the city with a festive glow, complemented by clear skies and an abundance of sunlight. Despite the highest wind speeds of the year, December is an attractive month for outdoor events and beach vacations. High visibility conditions in Porto Alegre make December ideal for sightseeing. Notwithstanding the high pressure and humidity, the city receives a constant influx of tourists during this month.

Temperature

In December, Porto Alegre notes an average high-temperature of a still moderately hot 29.8°C (85.6°F), hardly different from the preceding month. Nighttime temperature lowers to an average of 19°C (66.2°F) in December.

Heat index

The heat index for December is calculated to be a sweltering 35°C (95°F). Incorporate additional safety actions, heat cramps and heat exhaustion are possible. Long-term activity may induce heatstroke.
Regarding the heat index, one should be aware it's determined by shaded settings and mild winds. Uninterrupted exposure to the sun may boost the heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'real feel', is an estimation of the warmth sensation when considering humidity levels. Factors such as metabolic variation, pregnancy, and physical activity play a role in one's impression of weather. Remember, direct sunlight exposure can heighten the heat impact and might increase the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values hold great significance to children. Children often fail to recognize the requirement to rest and rehydrate. Thirst, being a late symptom of dehydration, underlines the importance of maintaining hydration, especially during ongoing physical activities.
Perspiration is the body's default response to elevated temperatures, as it promotes the evaporation of sweat to achieve cooling. In situations of high air temperature combined with high humidity (significant heat index), the body's ability to perspire is reduced, heightening the sense of warmth. With body temperatures on the rise, inefficient heat shedding can lead to dehydration and its associated complications.

Humidity

December is the least humid month, with an average relative humidity of 71%.

Rainfall

In Porto Alegre, during December, the rain falls for 13.7 days and regularly aggregates up to 60mm (2.36") of precipitation. In Porto Alegre, Brazil, during the entire year, the rain falls for 148.3 days and collects up to 805mm (31.69") of precipitation.

Sea temperature

In Porto Alegre, the average seawater temperature in December is 22.7°C (72.9°F).
Note: If you're wary of the cold, the surrounding conditions—sunshine, wind, and air temperature become crucial when swimming in 22.7°C (72.9°F) waters. Olympic standards, for reference, are set between 25°C (77°F) and 28°C (82.4°F).

Daylight

The month with the longest days is December, with an average of 14h and 0min of daylight.
On the first day of December in Porto Alegre, sunrise is at 05:15 and sunset at 19:12. On the last day of the month, sunrise is at 05:26 and sunset at 19:29 -03.

Sunshine

With an average of 8.3h of sunshine, December has the most sunshine of the year.

UV index

With an average maximum UV index of 7, December is the month with the highest UV index in Porto Alegre. A UV Index of 6 to 7 symbolizes a high health vulnerability from exposure to the Sun's UV rays for average individuals.
Note: In December, the average maximum UV index of 7 translates into the following recommendations:
Persist with precautions and heed sun safety advice. Prevention of sunburn is compulsory. Attempt to stay under shade and limit exposure to the Sun between 10 a.m. and 4 p.m., when UV radiation is at its peak. Remember, devices such as parasols or canopies might not provide complete sun protection. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly. Be mindful! Sand and water reflections can up the Sun's UV exposure.