Last updated: August 21, 2025
In September, Heredia, Costa Rica, showcases a captivating tropical climate characterized by a maximum temperature of 25°C (78°F) and an average of 19°C (66°F), providing a pleasant escape from the heat. As the month unfolds, Humidity levels hover around a notable 81%, contributing to the lush, vibrant landscapes. However, prepare for rainy days, as precipitation reaches a substantial 379 mm (14.9 in) across 29 days, creating a refreshing atmosphere. Embrace the beauty of this rainforest region, where the richness of nature flourishes amidst the rain.
In September, Heredia, Costa Rica experiences a delightful blend of mild temperatures, with minimums around 14°C (58°F) and maximums peaking at 25°C (78°F). The average remains a comfortable 19°C (66°F), making it an appealing time for visitors and locals alike. As the rainy season progresses, September's slightly cooler nights invite cozy evenings, while the daytime warmth encourages exploration. This month features a subtle ebb in temperatures compared to the lingering warmth of August, highlighting a gradual transition towards the drier months ahead.
In September, Heredia, Costa Rica, experiences a significant uptick in precipitation, with an impressive 379 mm (14.9 in) of rain over 29 days. This marks a continuation of the region's wet season, following the heavy downpours of May and June. While the rainfall amounts slightly diminish compared to the previous months, September is notable for its consistent rainy days, mirroring the patterns seen in August. Such lush conditions not only contribute to the vibrant, green landscapes typical of the region but also herald the onset of even wetter October, when rainfall peaks. As the rainy season progresses, the atmosphere in Heredia becomes rich with the soothing sounds of raindrops, providing a refreshing backdrop to daily life.
In September, Heredia, Costa Rica experiences a significant shift in humidity levels, with an average of 81%. This marks a slight decrease from the peak months of June and July, which boast humidity levels of 84% and 85%, respectively. Following a trend of increasing humidity from the dry months of January through May, where levels hover around 66-69%, September’s humidity signals the tail end of the rainy season. As the month transitions into October, humidity remains relatively high at 80%, maintaining a tropical atmosphere that characterizes this region. Overall, Heredia’s humid backdrop is not only vital for its lush landscapes but is also a key aspect of life in this vibrant Costa Rican locale.
In September, Heredia, Costa Rica, continues to experience extreme UV Index levels, maintaining a steady reading of 14. This aligns with the consistently high values recorded throughout the previous months, where the UV Index remained persistently elevated, peaking at 16 in April. With a uniform burn time of just 10 minutes, residents and visitors alike must remain vigilant about sun exposure this month. As the year progresses towards October, the UV Index does begin to hover around 15, indicating that the sun's intensity will remain a significant factor in outdoor activities. For those looking to plan their sun-soaked adventures safely, it's crucial to stay informed about local UV levels by checking the Heredia UV Index.
UV Risk Categories
September in Heredia, Costa Rica, brings a delightful shift in sunshine, with 249 hours of golden rays kissing the landscape. Following the peak summer months of March and April, which boast well over 300 hours of sunlight, September’s hours dip slightly yet remain vibrant, showcasing the region's continued allure. As the rainy season progresses, this month finds a balance, offering more sun than some of its preceding summer companions like July and August. While June leads into the heart of the rainy season with only 244 hours, September stands as a transition, hinting at the promising brightness of October and the upcoming festive season. With its gentle warmth and inviting light, September is a testament to Heredia's enchanting climate, blending rain with radiant sun.
In Heredia, Costa Rica, September marks a notable dip in sunshine, with only a 9% chance of clear skies. This trend is part of a broader pattern, as the region transitions from the relatively drier months earlier in the year. Following the peak sun months of January through March, where the likelihood of sunny weather hovers around the 40-47% mark, the chances begin to wane significantly as the rainy season sets in. As it progresses into the heart of the rainy season, particularly from June to August, sunlight becomes a rare commodity, culminating in September’s persistent cloud cover and drizzle. For those seeking brighter days in Heredia, September's weather serves as a reminder that even tropical paradises occasionally take a break from the sun.
In September, Heredia, Costa Rica, enjoys a consistent 12 hours of daylight, continuing the trend established in the preceding months of June through August. This period of ample sunlight reflects the region's tropical climate, where daylight duration remains relatively steady throughout the year. As the days begin to shorten with the approach of October, the daylight gradually decreases to 11 hours, reminiscent of the earlier months of January and February. The stability of daylight hours highlights Heredia's unique position near the equator, where variations in daylight are less pronounced compared to more temperate regions, offering residents and visitors alike a vibrant outdoor experience year-round.
In September, the winds in Heredia, Costa Rica start to shift ever so subtly, with an average speed of just 1.3 m/s (3 mph). This slight breeze, reminiscent of the waning rainy season, provides a gentle respite from the tropical warmth. The trend for the month marks a continuation of the lower wind speeds observed from June to August, where the winds were even more subdued, reaching a minimum of 1.2 m/s (3 mph) in August. While September’s winds remain mild, they precede a gradual uptick in wind speeds as the year transitions to its final months—November and December promise a return to breezier conditions. This cyclical pattern not only reflects the region's climatic nuances but also offers a tranquil atmosphere perfect for enjoying the lush beauty of Heredia.
Weather in Heredia varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Heredia, focusing on differences in temperature, rainfall, humidity, and UV levels.
In September, the weather is characterized by a mild average temperature of 19°C (66°F), with daily highs reaching up to 25°C (78°F) and lows around 14°C (58°F). This month experiences significant rainfall, averaging 379 mm (14.9 in) over 29 days, making it the wettest month of the year, with a humidity level of 81%. In contrast, January has a slightly cooler average temperature of 17°C (63°F) with maximum temperatures around 24°C (76°F) and a minimum of 11°C (53°F). January sees much less precipitation at 93 mm (3.7 in) over just 11 days, and the humidity is lower at 68%, providing a drier and more comfortable start to the year. For more detailed information, you can check Heredia weather in January.
September and February present notable contrasts in weather patterns. September features a warmer climate with average temperatures ranging from a minimum of 14°C (58°F) to a maximum of 25°C (78°F). However, it is characterized by high humidity at 81% and significant rainfall, totaling 379 mm (14.9 in) over 29 days. In contrast, February experiences slightly cooler temperatures, with a minimum of 11°C (52°F) and an average of 17°C (64°F). This month has much less precipitation, totaling 43 mm (1.7 in) over just 12 days, and a lower humidity level of 68%. For more details, you can check Heredia weather in February.
In September, the weather tends to be warmer and more humid, with average temperatures ranging from a minimum of 14°C (58°F) to a maximum of 25°C (78°F) and an average of 19°C (66°F). The month also sees considerable rainfall, totaling 379 mm (14.9 in) across 29 rainy days and an overall humidity of 81%. In contrast, March features slightly cooler temperatures, with a minimum of 11°C (53°F) and an average of 18°C (64°F), while still reaching a maximum of 25°C (76°F). This month experiences significantly less rainfall, with only 49 mm (1.9 in) over 14 days and lower humidity at 66%. For more detailed insights on March weather, you can check Heredia weather in March.
When comparing the weather in September and April, both months showcase similar average temperatures, hovering around 19°C (66°F). However, September tends to be wetter, with a significant amount of precipitation at 379 mm (14.9 in) over 29 days, resulting in a humid environment with an 81% humidity level. In contrast, April sees much less rainfall, totaling 113 mm (4.4 in) over 23 days, and a lower humidity of 67%. This difference not only influences the atmospheric feel but also highlights the transition from the rainy season in September to a slightly drier climate in April. For more specific information on April weather, you can visit Heredia weather in April.
In comparing the weather of September and May, both months showcase similar average temperatures, with September ranging from a minimum of 14°C (58°F) to a maximum of 25°C (78°F), while May sees a slightly higher maximum of 26°C (79°F) under comparable minimum temperatures. However, May is generally drier, receiving 425 mm (16.7 in) of precipitation over 29 days, compared to September's 379 mm (14.9 in) during the same number of days. Furthermore, September experiences higher humidity levels at 81%, compared to May's more comfortable 69%. For those interested in a more detailed look at May weather, Heredia weather in May offers additional insights.
In comparing the weather of September and June, both months exhibit similar average temperatures, hovering around 19°C (66°F). However, September tends to be slightly cooler at its minimum temperature of 14°C (58°F) compared to June's minimum of 15°C (59°F). While June has a maximum temperature of 26°C (78°F), September also reaches a similar high of 25°C (78°F). Rainfall is more pronounced in September, with 379 mm (14.9 in) over 29 days, compared to June's 341 mm (13.4 in) over 28 days. Additionally, September maintains a humidity level of 81%, slightly lower than June’s 84%. This makes both months quite humid, but September appears to be wetter overall. For more details, you can check Heredia weather in June.
In comparing the weather between September and July, we can see some notable differences. Both months have similar average temperatures, ranging from a minimum of 14-15°C (58-59°F) and a maximum of 25°C (77-78°F), but September tends to be slightly cooler on average. The most striking contrast lies in the precipitation levels; September receives significantly more rainfall, with 379 mm (14.9 in) over 29 days compared to July’s 266 mm (10.5 in) across 28 days. This leads to higher humidity in September at 81%, compared to July's 85%, making July feel a bit more humid overall. For more detailed information, you can check Heredia weather in July.
In comparing the weather of September and August, we notice that September tends to be slightly cooler, with a minimum temperature of 14°C (58°F) compared to August's 15°C (59°F). Both months share a similar average temperature of 19°C (66°F), but August has a marginally higher maximum temperature at 26°C (79°F) versus September's 25°C (78°F). Rainfall is notably higher in September, with 379 mm (14.9 in) of precipitation over 29 days, compared to August's 304 mm (12.0 in) across 28 days. Humidity levels remain similar, with September at 81% and August at 82%. For a closer look at August weather specifics, visit Heredia weather in August.
September and October share similar temperature ranges, with minimums at 14°C (58°F), average temperatures of 19°C (66°F), and maximums reaching 25°C (78°F). However, October experiences a notable increase in precipitation, totaling 517 mm (20.4 in) compared to September's 379 mm (14.9 in), despite both months having 29 rainy days. The humidity remains fairly consistent, with September at 81% and October at 80%. For more details on the specific weather conditions in October, you can visit Heredia weather in October.
In comparing the weather of September and November, we see a slight decrease in average temperatures and precipitation levels. September showcases a range of temperatures from a minimum of 14°C (58°F) to a maximum of 25°C (78°F), with an average of 19°C (66°F) and significant rainfall totaling 379 mm (14.9 in) over 29 days, resulting in a high humidity level of 81%. In contrast, November experiences a similar minimum temperature of 14°C (57°F) but has a slightly lower average of 18°C (65°F) and a maximum of 24°C (75°F). Precipitation is also reduced to 260 mm (10.3 in) over 24 days, with humidity dropping slightly to 80%. For more detailed information on November weather, visit Heredia weather in November.
In September, the weather is characterized by slightly warmer temperatures, with lows around 14°C (58°F) and highs reaching up to 25°C (78°F), accompanied by a high level of precipitation at 379 mm (14.9 in) over 29 days. This results in a humid atmosphere with humidity levels at 81%. In contrast, December sees a minor decrease in temperature, with a minimum of 12°C (55°F) and a maximum of 24°C (75°F), but experiences significantly less rainfall, totaling 156 mm (6.1 in) across 16 days. This difference leads to lower humidity levels at 72% in December, making it a more comfortable month overall. For more detailed insights, you can check Heredia weather in December.
September in Heredia showcases a distinctive blend of mild temperatures and high humidity, making it a unique month compared to the rest of the year. With frequent rainfall—often resulting in nearly a full month of wet days—the lush surroundings reach their peak vibrancy. While maximum temperatures hover around comfortable levels, the heavy precipitation creates a refreshing atmosphere that is a stark contrast to the drier months. This combination of warmth and rain not only nourishes the landscape but also calls for a cozy embrace of nature, drawing in those who appreciate the lush beauty of the rainy season. To explore more about how this weather fits into the larger climate context, visit Heredia Climate.