Last updated: August 21, 2025
September in Jaco, Costa Rica is characterized by warm temperatures and a tropical ambiance. With an average temperature of 26°C (80°F) and daily highs reaching up to 28°C (83°F), visitors can expect a comfortable yet humid environment, averaging 81% humidity. However, this month is marked by significant rainfall, as 461 mm (18.2 in) of precipitation falls across an impressive 29 days, creating lush landscapes and vibrant scenery. Those planning to explore Jaco during September should be prepared for the frequent showers, which contribute to the area's stunning natural beauty.
In September, Jaco, Costa Rica experiences a warm tropical climate, with temperatures remaining consistently pleasant. The month typically sees minimums around 25°C (77°F), while averages dip slightly to 26°C (80°F) and maximums reach 28°C (83°F). This shift marks a subtle decline in warmth compared to the preceding months, as the summer fades into the rainy season. Despite the reduced averages, the temperatures remain inviting for beachgoers and nature enthusiasts alike, making September a charming time to explore Jaco’s stunning coastline and lush surroundings. This month’s comfortable warmth, combined with the vibrant green landscapes, offers a unique allure for those seeking a blend of relaxation and adventure in paradise.
In September, Jaco, Costa Rica, experiences a significant spike in precipitation, recording an impressive 461 mm (18.2 in) of rain over 29 days. This month continues the trend of the wet season, following the heavy downpours of August, which peaked at 495 mm (19.5 in). As the rainy season progresses, September showcases a slight decline compared to its predecessor, yet still remains impactful, contributing to the lush landscapes that attract visitors. The consistent rainfall also aligns with the preceding months of June and July, which averaged around 393 mm (15.5 in) and 358 mm (14.1 in), highlighting a pattern of robust rainfall that defines this coastal region. As October approaches, precipitation is expected to escalate further, culminating in an average of 638 mm (25.1 in), signifying that Jaco's rich biodiversity thrives amidst these abundant waters.
In September, Jaco, Costa Rica experiences a notable humidity level of 81%, which is slightly lower than the peak summer months of June and July, but still significantly higher than the early part of the year. This month sits comfortably within a high humidity trend that creeps in around June, peaking during the heart of the rainy season. Following September, humidity begins to decline gradually as October and November approach, settling back to 80%, thus hinting at the transition into the drier months. Overall, while September maintains the tropical feel of the region, the slight dip in humidity may offer a welcomed relief to visitors seeking to enjoy the lush, vibrant landscape without the excessive mugginess typical of mid-year.
In September, Jaco, Costa Rica maintains a UV Index of 13, categorizing it as extreme and ensuring that the burn time remains a swift 10 minutes. This trend reflects the prevailing conditions experienced throughout the year, where consistently high UV levels dominate from January to July, often peaking at 14. While August and September see a slight dip to 13, caution is still warranted, as the potential for sunburn remains significant. As the seasons transition toward October, the UV Index stabilizes, continuing to underscore the importance of sun protection for beachgoers and outdoor enthusiasts alike. For detailed insights and tips on managing UV exposure in this vibrant region, visit Jaco UV Index.
UV Risk Categories
In September, Jaco, Costa Rica, welcomes 241 hours of sunshine, making it a charming retreat for those seeking warmth before the rains of the later months set in. While September may not boast the peak sunshine hours, it stands resilient amidst a summer that typically yields brighter days. January to March spark the year with an impressive surge, averaging around 300 hours, before gently tapering off as the rainy season approaches. Interestingly, as August offers only 238 hours, September's slight rise hints at a hopeful transition, making it a perfect time for visitors to enjoy both the remaining sun and lush green landscapes. This gradual shift underscores Jaco's unique appeal, balancing sunshine and the enchanting rhythm of tropical weather throughout the year.
In Jaco, Costa Rica, the likelihood of sunny weather takes a notable dip in September, with only 12% chance of sunshine. This trend reflects the transition into the rainy season, where cloud cover and precipitation reign supreme. In contrast, the earlier months like January and March boast more favorable conditions, with chances of sunshine reaching 54% and 58%, respectively. As the rainy season progresses from the end of summer into fall, September stands out as one of the cloudiest months. However, hope is on the horizon with the return of brighter days beginning in October, when the likelihood of sunshine increases to 18%. Travelers planning a visit should prepare for rain, but remember that in Costa Rica, even a brief glimpse of sun can create magical moments amid the lush landscape.
In September, Jaco, Costa Rica, enjoys a consistent 12 hours of daylight, mirroring the trend seen through much of the preceding summer months. As the year transitions from the longer days of March through August, the daylight duration stabilizes, offering ample time for sun-soaked activities and breathtaking sunsets. This period highlights the region's remarkable climate, where daylight remains abundant even as it begins to taper off into the wetter months of October and November, which will once again bring back the shorter 11-hour days. Whether you're surfing the Pacific waves or exploring lush jungles, September's well-balanced daylight ensures there's plenty of time to soak in the natural beauty and vibrant culture of this tropical paradise.
In September, the winds in Jaco, Costa Rica, settle into a gentle rhythm, averaging 2.6 m/s (6 mph), similar to several months prior. This soothing breeze provides a comfortable backdrop for beachgoers and surfers alike, echoing the wind patterns of earlier months like January through April. Interestingly, July marks a slight dip in wind speed, while August sees a brief uptick to 3.2 m/s (7 mph), perhaps hinting at late summer's vibrant energy. As the month transitions into October, winds pick up slightly, with an average of 2.9 m/s (6 mph), suggesting a return to the more dynamic wind conditions of the season. Overall, September's winds contribute to Jaco’s tranquil allure, maintaining a consistent and inviting atmosphere for all who visit.
Weather in Jaco varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Jaco, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January offer contrasting weather conditions, despite their similar warm temperatures. In September, the temperatures range from a minimum of 25°C (77°F) to a maximum of 28°C (83°F) with an average of 26°C (80°F). However, this month is marked by significant rainfall, accumulating 461 mm (18.2 in) over 29 days, leading to high humidity levels around 81%. In contrast, January presents a slightly warmer average temperature of 27°C (81°F) with highs reaching 29°C (85°F) and minimal rainfall of only 36 mm (1.4 in) over just 7 days, resulting in a more comfortable humidity level of 68%. For more detailed information, you can visit Jaco weather in January.
September weather is characterized by high humidity and significant rainfall, with average temperatures ranging from a minimum of 25°C (77°F) to a maximum of 28°C (83°F) and a staggering 461 mm (18.2 in) of precipitation over 29 days. In contrast, February experiences slightly warmer temperatures, with averages reaching a maximum of 29°C (85°F) but offers a much drier climate, receiving only 12 mm (0.5 in) of rain over just 3 days. The humidity drops to 68%, making February a more pleasant month for outdoor activities compared to the wet and humid conditions of September. For more details, you can check Jaco weather in February.
When comparing the weather in September and March, notable differences arise in temperature and precipitation. September is marked by consistently warm temperatures, with minimums around 25°C (77°F) and maximums reaching up to 28°C (83°F), but it also experiences high humidity at 81% and significant rainfall of 461 mm (18.2 in) over 29 days. In contrast, March sees slightly warmer average temperatures, peaking at 29°C (85°F) while maintaining a lower humidity of 66%. Rainfall during March is minimal, with only 13 mm (0.5 in) over just 3 days, making it a much drier month. For more detailed information about the weather in March, you can check out Jaco weather in March.
In September, the weather tends to be cooler with average temperatures ranging from a minimum of 25°C (77°F) to a maximum of 28°C (83°F), while experiencing higher humidity at 81%. This month also sees significant rainfall, accumulating 461 mm (18.2 in) over 29 rainy days. In contrast, April offers slightly warmer conditions, with average temperatures from 25°C (77°F) to 29°C (85°F) and a lower humidity level of 67%. Additionally, April has considerably less rainfall, totaling 130 mm (5.1 in) across 21 days. For more specific details about the weather in April, you can visit Jaco weather in April.
Comparing the weather in September and May reveals some interesting contrasts. Both months have a similar minimum temperature of around 25°C (77°F), but May typically sees slightly warmer average and maximum temperatures, with an average of 27°C (81°F) and a maximum of 29°C (84°F). In terms of precipitation, September experiences 461 mm (18.2 in) over 29 days, while May has a marginally higher total of 474 mm (18.7 in) across 30 days. Additionally, humidity levels in September are notably higher at 81%, compared to May's more comfortable 69%. For more detailed insights, you can check out the specific conditions through this link: Jaco weather in May.
In comparing the weather of September and June, both months exhibit warm temperatures with minimal variation. September has a slightly lower average temperature of 26°C (80°F) compared to June’s 27°C (80°F) and a maximum of 28°C (83°F) versus June's 29°C (84°F). However, September experiences more precipitation, with 461 mm (18.2 in) compared to June's 393 mm (15.5 in), while both months share the same number of rainy days—29. Humidity levels are also similar, with September at 81% and June slightly higher at 84%. For more detailed information about June weather, you can check Jaco weather in June.
In comparing the weather between September and July, we see some notable similarities and differences. Both months feature a minimum temperature of around 25°C (77°F), with July slightly warmer on average at 27°C (80°F) compared to September's average of 26°C (80°F). The maximum temperatures are also slightly higher in July, reaching up to 29°C (84°F) versus September's maximum of 28°C (83°F).
However, September experiences significantly more precipitation, with 461 mm (18.2 in) falling over 29 days, compared to July’s 358 mm (14.1 in) over 30 days. Humidity levels are also marginally higher in July at 85%, compared to 81% in September. This moisture may contribute to the consistent rainfall in both months. For more details on July weather, you can check Jaco weather in July.
In comparing the weather of September and August, both months exhibit similar temperature ranges, with September having a minimum temperature of 25°C (77°F) and an average temperature of 26°C (80°F), just slightly cooler than August, which maintains an average of 27°C (80°F). While the maximum temperature remains steady at 28°C (83°F) for both months, September experiences a decrease in precipitation, totaling 461 mm (18.2 in) over 29 days, compared to August’s 495 mm (19.5 in) over 30 days. Humidity levels are also quite similar, with September at 81% and August slightly higher at 82%. For more detailed information on August weather patterns, you can refer to Jaco weather in August.
In September, the weather is characterized by warm temperatures, with minimums around 25°C (77°F) and maximums reaching 28°C (83°F), while maintaining an average temperature of 26°C (80°F). However, this month also sees significant rainfall, with a total precipitation of 461 mm (18.2 in) spread over 29 days, and humidity levels hovering around 81%.
Transitioning into October, the temperatures remain consistent, with a similar range of 25°C (77°F) to 28°C (82°F) and an average of 26°C (79°F). Nonetheless, October experiences an increase in precipitation, totaling 638 mm (25.1 in) across 30 days, while humidity slightly decreases to 80%. For more details on October weather, you can check out Jaco weather in October.
In comparing the weather between September and November, both months showcase similar temperature ranges, with minimums around 25°C (77°F), average temperatures at 26°C (79°F), and maximums reaching 28°C (82°F). However, September is significantly wetter, receiving 461 mm (18.2 in) of precipitation across 29 days, while November experiences only 303 mm (11.9 in) of rainfall over 26 days. Additionally, humidity levels are slightly lower in November, at 80%, compared to September's 81%. For more detailed information about the weather in November, you can check Jaco weather in November.
In comparing the weather between September and December, September is marked by slightly higher humidity levels at 81%, contributing to a more muggy atmosphere. With temperatures ranging from a minimum of 25°C (77°F) to a maximum of 28°C (83°F), it maintains an average of 26°C (80°F). In addition, September sees significantly more rainfall, with 461 mm (18.2 in) over 29 days. In contrast, December offers slightly warmer temperatures, with an average of 27°C (80°F) and a maximum of 29°C (84°F), but much lower precipitation at 125 mm (4.9 in) over 16 days, resulting in a drier feel. For more detailed information on December weather in Jaco, visit Jaco weather in December.
September in Jaco brings a unique climatic charm, characterized by high humidity levels and frequent rainfall, setting it apart from other months. With an average temperature around 26°C (80°F), this time of year feels pleasantly warm yet offers a refreshing contrast thanks to the almost daily showers. Unlike the drier months, the abundant precipitation transforms the landscape, resulting in lush greenery and vibrant surroundings, while the cooling rains provide a welcome respite from the tropical heat. If you're curious about the broader climate trends, check out Jaco Climate for more insights.