Last updated: August 21, 2025
December in Rio das Ostras, Brazil presents a vibrant tropical climate, with maximum temperatures reaching 34°C (93°F) and an average of 25°C (78°F), making it an inviting destination for sun-seekers. The weather, however, is accompanied by notable humidity levels of 81%, contributing to a lush, tropical ambiance. Travelers should be prepared for a total precipitation of 233 mm (9.2 in) spread over approximately 20 days, ensuring that the lush beauty of the surroundings is vividly highlighted. With its blend of warmth and occasional rain, December offers a unique experience of Brazilian summer, perfect for those looking to explore both beachside relaxation and the rich culture of this charming coastal town.
In December, Rio das Ostras experiences a delightful transition towards the peak of summer, with temperatures ranging from a mild 16°C (61°F) at night to a comfortable average of 25°C (78°F) during the day. As the month progresses, daytime highs typically reach about 34°C (93°F), creating an inviting atmosphere perfect for beachgoers and outdoor enthusiasts. This month's temperatures mark a slight increase compared to the preceding months, signaling the arrival of warmer weather. Overall, December in Rio das Ostras sets the scene for vibrant summer days, making it an ideal time for relaxation and adventure along its beautiful coastlines.
In December, Rio das Ostras experiences a significant uptick in precipitation, with an impressive 233 mm (9.2 in) of rain falling over the course of 20 days. This marks a continuation of the trend observed throughout the wet season, characterized by increased rainfall and consistent cloud cover. The intensity of December rains is only slightly less than the record-breaking 235 mm (9.3 in) witnessed in November, indicating a robust and persistent rainy period as the year comes to a close. This November-December duo stands out sharply against the drier months preceding them, where averages plummeted to mere 34 mm (1.3 in) in June and 19 mm (0.7 in) in July. As December wraps up the year, residents and visitors alike can expect lush landscapes and vibrant blooms, driven by this late surge in moisture.
In Rio das Ostras, Brazil, December marks a slight uptick in humidity levels, settling at 81% after a gradual decline from the peak of 86% in February. This trend reveals a seasonal pattern where humidity is particularly high in the summer months, gradually decreasing to its lowest point of 74% in October before climbing back up as the year closes. December's humidity creates a balmy atmosphere, bridging the comfortable, drier conditions of late autumn with the refreshing warmth of summer. The consistent humidity around the 80% mark provides a lush, vibrant setting for both locals and visitors, enhancing the natural beauty of this coastal paradise.
In Rio das Ostras, Brazil, the December UV Index soars to 16, marking a return to extreme exposure levels reminiscent of earlier months in the year. This intense UV radiation is consistent with the striking trend observed from January through March, where values hovered around 16 to 13—indicating just 10 minutes of burn time. As the year progresses into the cooler months, the index dips briefly, with May to August witnessing a slightly decreased risk, classified as very high and high, allowing for a more forgiving 15 to 25 minutes of skin exposure. However, the reins tighten again in the latter months, emphasizing the importance of sun safety in this vibrant coastal haven. For a complete look at the UV Index throughout the year, refer to Rio das Ostras UV Index.
UV Risk Categories
December marks a radiant climax to the year in Rio das Ostras, Brazil, boasting an impressive 331 hours of sunshine. This month stands out not only as the sunniest in the year but also reflects a delightful trend, with sunshine hours generally increasing as the year progresses towards summer. From a low of 286 hours in January, the coastal charm of Rio enjoys a steady ascent in daylight, peaking in the festive spirit of December. This flourishing sunlight not only brightens the beaches but also invites locals and travelers alike to immerse themselves in the vibrant culture and stunning landscapes that Rio das Ostras has to offer. As the sunshine envelops the town, it creates a captivating backdrop for unforgettable experiences.
In December, Rio das Ostras sees a 36% chance of sunny weather, marking a transitional phase as the year winds down. While this percentage is lower than the peak sunny months of July and June, which boast chances over 50%, it still offers a delightful mix of ocean breezes and occasional sunshine. Interestingly, December’s sunny likelihood is a step up from the somewhat gloomy weeks of October, where the chances plummet to 16%. This month sits amidst a steady trend towards brighter days, allowing visitors to enjoy the vibrant coastal landscape, albeit with the understanding that clearer skies aren't guaranteed.
In Rio das Ostras, Brazil, the daylight duration reveals a fascinating cycle throughout the year. As we transition from the summer months of January and February, where daylight stretches for 13 and 12 hours respectively, we begin to notice a gradual decrease into the cooler autumn months of March and April, with daylight lasting 12 and 11 hours. This trend continues into the winter months of June and July, where the shortest days yield 10 hours of sunlight. However, as spring approaches in August and September, daylight nudges back up to 11 hours, revitalizing the landscape. By the time December rolls around, residents enjoy a refreshing return to 13 hours of daylight, echoing the long days of the new year. This cyclical pattern not only highlights the natural rhythm of the seasons but also sets the stage for the vibrant energy that Rio das Ostras is known for.
As December arrives in Rio das Ostras, the wind gently whispers through the coastal landscapes, averaging a pleasant 2.7 m/s (6 mph). This slight breeze marks a continuation of a trend seen throughout the year, where wind speeds tend to fluctuate but remain relatively mild, with the highest averages occurring earlier in the year. Following the busier months of September and August, both reaching around 3.7 m/s (8 mph), December's soothing winds offer a sense of tranquility as the region transitions into the summer season. Though less forceful than its predecessors, the December winds still invite beachgoers and nature lovers to bask in the coastal charm, setting the stage for leisurely, sun-soaked days ahead.
Weather in Rio das Ostras varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Rio das Ostras, focusing on differences in temperature, rainfall, humidity, and UV levels.
December and January offer distinct weather experiences in Rio das Ostras. In December, temperatures range from a minimum of 16°C (61°F) to a maximum of 34°C (93°F), with an average of 25°C (78°F). The month is characterized by significant rainfall, totaling 233 mm (9.2 in) over about 20 days, and humidity levels hover around 81%. In contrast, January sees warmer temperatures, with a minimum of 20°C (68°F) and a maximum of 36°C (97°F), averaging at 27°C (81°F). Rainfall decreases significantly to 127 mm (5.0 in) spread over just 12 days, while humidity rises slightly to 85%. For more details on January weather, visit Rio das Ostras weather in January.
In December, the weather in Rio das Ostras features a range of temperatures, with a minimum of 16°C (61°F), an average of 25°C (78°F), and a maximum of 34°C (93°F). This month sees significant rainfall, with 233 mm (9.2 in) spread over 20 days, and humidity levels are relatively high at 81%.
In contrast, February experiences slightly warmer conditions, presenting a minimum temperature of 20°C (68°F), an average of 26°C (79°F), and a maximum reaching 36°C (97°F). While the precipitation is lower at 190 mm (7.5 in) over the same number of rainy days, humidity rises to 86%, making the air feel even warmer. For more detailed insights, you can check Rio das Ostras weather in February.
In comparing the weather of December and March, both months offer warm temperatures, but December tends to be slightly cooler overall. December's average temperature hovers around 25°C (78°F) with a maximum of 34°C (93°F), while March sees a slight increase, averaging 26°C (79°F) and peaking at 35°C (96°F). Precipitation is more abundant in December with 233 mm (9.2 in) falling over 20 days, compared to March, which receives 185 mm (7.3 in) over 17 days. Humidity is relatively high in both months, with December at 81% and March at 84%. For more detailed information on March weather specifically, you can check Rio das Ostras weather in March.
In December, the weather is typically warm and humid, with temperatures ranging from a minimum of 16°C (61°F) to a maximum of 34°C (93°F) and an average of 25°C (78°F). This month also sees significant rainfall, totaling 233 mm (9.2 in) over approximately 20 days, contributing to a high humidity level of 81%. Conversely, April features slightly cooler temperatures, with a minimum of 16°C (62°F) and a maximum of 35°C (96°F), averaging around 24°C (76°F). Precipitation in April drops to 73 mm (2.9 in) over about 12 days, with humidity remaining high at 82%. For more specific details, you can refer to Rio das Ostras weather in April.
In December, the weather in Rio das Ostras is notably warmer, with average temperatures ranging from a minimum of 16°C (61°F) to a maximum of 34°C (93°F). This month also experiences higher precipitation levels, with 233 mm (9.2 in) of rain falling over 20 days and humidity peaking at 81%. In contrast, May offers slightly cooler temperatures, with averages between 13°C (56°F) and 34°C (93°F) while seeing significantly less rainfall—only 68 mm (2.7 in) across just 9 days and a humidity level of 80%. For more detailed information, check out Rio das Ostras weather in May.
In December, the weather in Rio das Ostras is characterized by warmer temperatures, with averages around 25°C (78°F) and maximums reaching up to 34°C (93°F). The month also sees significant rainfall, totaling 233 mm (9.2 in) spread across about 20 days, leading to a high humidity level of 81%. In contrast, June features cooler conditions, with average temperatures dropping to 22°C (72°F) and maximums of 33°C (91°F). Rainfall is much less frequent and lighter, totaling only 34 mm (1.3 in) over approximately 7 days and a humidity level of 78%. For more detailed information on the weather in June, you can check Rio das Ostras weather in June.
In December, temperatures in Rio das Ostras range from a minimum of 16°C (61°F) to a maximum of 34°C (93°F), averaging around 25°C (78°F). The month is characterized by significant rainfall, with about 233 mm (9.2 in) of precipitation over 20 days and high humidity at 81%. In contrast, July features milder weather, with temperatures ranging from 12°C (53°F) to 33°C (91°F) and an average of 21°C (70°F). July is considerably drier, receiving only 19 mm (0.7 in) of rain over just 5 days, and the humidity is slightly lower at 77%. For a detailed look at July weather in this region, check out Rio das Ostras weather in July.
In December, the weather in Rio das Ostras is characterized by warmer temperatures, with an average of 25°C (78°F) and highs reaching up to 34°C (93°F). The month is also marked by significant rainfall, totaling 233 mm (9.2 in) across approximately 20 days, contributing to a high humidity level of 81%. In contrast, August experiences cooler conditions, with average temperatures around 21°C (70°F) and a minimum of 13°C (55°F). Precipitation is notably lower at 53 mm (2.1 in) over just 10 days, and humidity is slightly reduced at 75%. For more details on August's climate, you can explore Rio das Ostras weather in August.
When comparing the weather in December and September, December tends to be warmer and wetter. December has an average temperature of 25°C (78°F), with maximums reaching up to 34°C (93°F), while September's average temperature is slightly lower at 23°C (74°F), peaking at 35°C (96°F). Additionally, December experiences significantly higher precipitation, with 233 mm (9.2 in) falling over 20 days, compared to September's 66 mm (2.6 in) over just 8 days. Humidity is also higher in December at 81%, compared to September's 75%. For more detailed information, you can check Rio das Ostras weather in September.
In comparing the weather of December and October, we notice that both months experience warm temperatures, with minimums around 16°C (61°F). However, December typically sees a slightly higher average temperature of 25°C (78°F) compared to October's 24°C (75°F). Interestingly, October can reach a maximum of 36°C (98°F), while December's maximum is somewhat lower at 34°C (93°F).
Precipitation levels also differ significantly between the two months; December receives 233 mm (9.2 in) of rain over approximately 20 days, whereas October has a milder total of 117 mm (4.6 in) over 15 days. Additionally, humidity is higher in December at 81%, compared to October's 74%. For more specific details on October's weather, you can visit Rio das Ostras weather in October.
In comparing the weather in December and November, we see that December tends to be slightly warmer, with an average temperature of 25°C (78°F) compared to November's 24°C (75°F). However, November boasts a higher maximum temperature of 36°C (98°F), while December's peak reaches 34°C (93°F). Both months experience significant rainfall, with December receiving 233 mm (9.2 in) over 20 days, just slightly less than November's 235 mm (9.3 in) over 18 days. Humidity levels are fairly similar, with December at 81% and November at 79%. For more detailed information about the weather in November, you can check out this link: Rio das Ostras weather in November.
In December, Rio das Ostras experiences a notable shift in weather, marked by warmer temperatures and increased humidity that create a vibrant, tropical atmosphere. Unlike the cooler months, visitors can expect a sultry climate, with average highs reaching around 34°C, making it the perfect time for beach activities and exploring the stunning coastline. However, this month also brings frequent rain, with up to 20 days of precipitation, contributing to the lush greenery that characterizes the region. For those planning to visit, understanding these conditions can make for a more enjoyable and memorable experience. To dive deeper into the seasonal changes in this beautiful locale, check out Rio das Ostras Climate.