Last updated: August 21, 2025
September in La Fortuna, Costa Rica unveils a captivating tropical climate, characterized by a maximum temperature soaring to 32°C (89°F) and a gentle average of 24°C (76°F). As the rainy season peaks, visitors can expect heavy precipitation, totaling 295 mm (11.6 in) over 28 days, enveloping the landscape in lush greenery. With an average humidity level of 80%, the air is thick and vibrant, creating a quintessential rainforest atmosphere. Whether you're exploring the stunning waterfalls or relaxing in the natural hot springs, September offers an immersive, enchanting experience for nature lovers and adventurers alike.
In La Fortuna, Costa Rica, September offers a tropical embrace with stable temperatures that reflect the region's lush environment. The month experiences minimums around 20°C (68°F), with averages of 24°C (76°F), and a maximum of 32°C (89°F), making it a comfortable yet warm time to visit. While September retains similar thermal characteristics to the preceding months of August and July, it's important to note the slight increase in nighttime warmth, which hints at the transition into the more humid rainy season. Despite the potential for showers, the mild temperatures and vibrant scenery invite travelers to explore the region's stunning waterfalls and rich biodiversity, making it a worthwhile experience amidst the rain.
September in La Fortuna, Costa Rica, marks a peak in the rainy season, delivering a significant 295 mm (11.6 in) of precipitation over 28 days. This month, often characterized by lush landscapes and vibrant greenery, is part of a broader trend showcasing the region's transition from the drier months earlier in the year, such as January with a mere 42 mm (1.6 in), to the heavy downpours typical of late rainy season months like October. September's rainfall, while substantial, is slightly less than October's expected 391 mm (15.4 in), indicating a gradual build-up in precipitation that supports the flourishing biodiversity of this tropical paradise. Visitors during this time can expect an immersive experience in nature, with rain showers interspersed with moments of stunning clarity, making it an enchanting month for exploring La Fortuna’s stunning scenery.
In September, La Fortuna, Costa Rica, experiences a notable rise in humidity with levels reaching 80%. This is part of a larger trend observed during the rainy season; humidity peaks in the summer months, starting from a milder 66% in January and climbing steadily through the year. After a sharp increase in June and July, when humidity soars to 74% and 85% respectively, September remains significantly damp but slightly lower than the earlier summer highs, setting the stage for lush landscapes and refreshing downpours. As the year progresses towards October, humidity begins to decline slightly, resting at 79%, yet the humidity remains consistently high, contributing to the region's vibrant ecosystem.
In September, La Fortuna experiences a UV Index of 13, categorizing it as extreme, with a burn time of just 10 minutes. This month maintains a trend consistent with the preceding summer months, where elevated UV levels are the norm, peaking in April at 15. Although September's UV Index does slightly dip from August's level, it remains a reminder of the potent sun in this tropical paradise. As you explore the breathtaking landscapes and vibrant wildlife of La Fortuna, be sure to protect yourself from the sun's intense rays. For more detailed information on the UV Index throughout the year in La Fortuna, visit La Fortuna UV Index.
UV Risk Categories
As September rolls into La Fortuna, Costa Rica, visitors can expect 262 hours of sunshine, slightly below the vibrant peak of 333 hours seen in March. This month marks a transition, where the sun still shines brightly but begins to taper off as the rainy season settles in. While not as abundant as the preceding summer months, September offers a delightful mix of warm, sunny days perfect for exploring the lush rainforests and captivating waterfalls. Consistently, the months from January to August display a generous share of sunshine, but as October approaches, we see a gradual decline, hinting at the shifting climate. Embrace the enchanting light of September, as the days are still long and bright, providing ample opportunity to experience the natural wonders of this stunning destination.
In La Fortuna, Costa Rica, September ushers in a notably gloomy weather pattern, with only an 11% chance of sunny days. This marks one of the lowest probabilities of sunshine throughout the year, following the particularly dreary months of August and June, which also dip below 15%. As the wet season peaks, visitors can expect frequent rain and overcast skies, contrasting sharply with the more inviting sunny periods of January (34%) and December (39%). Those planning a trip in September should be prepared for the lush, vibrant scenery that accompanies the rain, but they might want to keep their flip-flops tucked away in favor of umbrellas!
In September, La Fortuna, Costa Rica, enjoys a consistent 12 hours of daylight, mirroring the trend established in the preceding months. As the region approaches the end of the rainy season, the enduring daylight duration provides ample opportunity for exploration and adventure amidst its lush landscapes. Early in the year, both January and February feature slightly shorter days with 11 hours of daylight, but as spring progresses into the warmer months—March through August—daylight extends to a gratifying 12 hours. This steady pattern continues through September, offering travelers a perfect blend of vibrant daylight and rich biodiversity before the days gradually shorten again in October.
In September, La Fortuna experiences a tranquil atmosphere with an average wind speed of 1.5 m/s (3 mph), mirroring the calm of August. This gentle breeze contributes to the lush, verdant landscapes that define the region, as the rainy season reaches its peak. Following the summer months with slightly more wind, the transition into fall brings a noticeable stillness, ideal for those seeking a serene escape. As the year progresses into October, this tranquility continues, hinting at the return of more noticeable breezes in November and December. Overall, September's mild winds encourage relaxation and appreciate the rich biodiversity that thrives in this enchanting corner of Costa Rica.
Weather in La Fortuna varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in La Fortuna, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January exhibit notable differences in weather patterns. In September, temperatures range from a minimum of 20°C (68°F) to a maximum of 32°C (89°F), with an average temperature of 24°C (76°F). This month is characterized by high humidity at 80% and significant rainfall, totaling 295 mm (11.6 in) spread over 28 days. In contrast, January offers milder conditions with temperatures ranging from a minimum of 14°C (58°F) to a maximum of 30°C (87°F) and an average of 23°C (74°F). The precipitation in January drops dramatically to just 42 mm (1.6 in) over 11 days, accompanied by lower humidity at 66%. For more detailed information, check La Fortuna weather in January.
September and February showcase contrasting weather patterns. In September, temperatures fluctuate from a minimum of 20°C (68°F) to a maximum of 32°C (89°F), with an average of 24°C (76°F). This month is characterized by high humidity at 80% and significant rainfall, recording 295 mm (11.6 in) across 28 days. In contrast, February tends to be drier and warmer, with temperatures ranging from a minimum of 17°C (63°F) to a maximum of 33°C (91°F), while maintaining an average of 24°C (75°F). Precipitation is markedly lower at just 18 mm (0.7 in) over 6 days, and humidity drops to 64%. For more detailed insights, you can check La Fortuna weather in February.
Comparing the weather in September and March reveals distinct differences in temperature and precipitation patterns. September tends to be more humid with an average humidity of 80% and significant rainfall totaling 295 mm over 28 days, resulting in a lush, green landscape. In contrast, March offers a drier climate with only 19 mm of rain falling over just 6 days and lower humidity at 63%, making it a more comfortable time for outdoor activities. Both months feature similar average temperatures around 24°C (76°F), but March can peak slightly higher with a maximum of 33°C (91°F) compared to September's 32°C (89°F). For a more detailed look at the March weather in La Fortuna, you can check out La Fortuna weather in March.
In comparing the weather of September and April, we see notable differences in temperature and precipitation patterns. September typically experiences warmer daytime temperatures, with a maximum of 32°C (89°F) and an average of 24°C (76°F), while April boasts slightly higher maximum temperatures at 34°C (93°F) and an average of 25°C (78°F). However, September is significantly wetter, with 295 mm (11.6 in) of rain over 28 days compared to just 52 mm (2.1 in) over 12 rainy days in April. Additionally, humidity levels are higher in September at 80%, compared to 63% in April. For a detailed look at April weather in La Fortuna, you can visit La Fortuna weather in April.
In comparing the weather of September and May, both months exhibit warm temperatures, with September averaging around 24°C (76°F) and May slightly warmer at 25°C (77°F). However, May boasts higher maximum temperatures, reaching up to 34°C (93°F), compared to September's peak of 32°C (89°F). Precipitation is significant in both months, with September receiving 295 mm (11.6 in) over 28 days and May slightly higher at 308 mm (12.1 in) over 25 days. Notably, September has a higher humidity level of 80%, while May's humidity stands at a more comfortable 63%. For a detailed overview of May weather in La Fortuna, you can refer to La Fortuna weather in May.
In comparing the weather between September and June, both months boast similar temperature ranges, with minimum temperatures around 20°C (68°F), and maximum temperatures peaking at 32°C (89°F in September and 90°F in June). However, September tends to be slightly cooler on average at 24°C (76°F), compared to June’s average of 25°C (77°F). Rainfall is notably high in both months, with September receiving about 295 mm (11.6 in) and June slightly more at 314 mm (12.4 in), both spread over approximately 28 rainy days. Humidity levels also differ, with September experiencing a higher humidity at 80%, while June maintains a more comfortable 74%. For more details on the weather in June, check out La Fortuna weather in June.
In September, the weather features slightly warmer temperatures compared to July, with minimums around 20°C (68°F) and maximums reaching up to 32°C (89°F), while July maxes out at 31°C (88°F). Both months have an average temperature of 24°C (76°F), but September experiences significantly higher precipitation, totaling 295 mm (11.6 in) over 28 days, in contrast to July's 146 mm (5.7 in) over the same number of days. Additionally, humidity is slightly lower in September at 80%, compared to July's 85%. For a more detailed look at July's weather in La Fortuna, you can check this link: La Fortuna weather in July.
In comparing the weather of September to that of August, both months exhibit similar temperature ranges, with minimums around 20°C (68°F), averages at 24°C (76°F), and maximums just shy of 32°C (89°F in September and 90°F in August). However, September tends to be slightly wetter, receiving 295 mm (11.6 in) of rainfall over 28 days compared to August's 257 mm (10.1 in) over 27 days. Additionally, humidity levels are marginally lower in September at 80%, while August experiences a higher average humidity of 82%. For more detailed insights, you can refer to La Fortuna weather in August.
In comparison to September, October maintains similar temperature patterns with a minimum of 20°C (68°F), an average of 24°C (75°F), and a maximum of 31°C (87°F). However, October sees an increase in precipitation, with 391 mm (15.4 in) recorded over 29 days, compared to September's 295 mm (11.6 in) across 28 days. Despite the rise in rainfall, the humidity remains relatively stable at 79%, slightly lower than September's 80%. For more specific insights on the climate during this month, check out La Fortuna weather in October.
September weather tends to be warmer and wetter compared to November. With minimum temperatures around 20°C (68°F) and maximums reaching up to 32°C (89°F), September sees an average temperature of 24°C (76°F). It also experiences significant rainfall, accumulating 295 mm (11.6 in) over 28 days, resulting in a humid environment with 80% humidity.
In contrast, November features slightly cooler temperatures, with minimums of 18°C (65°F) and maximums of 30°C (87°F), maintaining the same average of 24°C (75°F). Rainfall decreases significantly to 169 mm (6.7 in) over 24 days, and the humidity is marginally lower at 79%. For more detailed information, you can check out La Fortuna weather in November.
In September, the weather is characterized by warmer temperatures, with average highs reaching up to 32°C (89°F) and significant rainfall, totaling 295 mm (11.6 in) over 28 days, contributing to a high humidity level of 80%. In contrast, December offers slightly cooler temperatures, averaging around 23°C (74°F) with maximums of 29°C (85°F) while experiencing much lower precipitation of 60 mm (2.3 in) spread over 20 days, and a decrease in humidity to 70%. The transition from September to December marks a shift from a notably wet season to a more comfortable climate, making December a more favorable time for outdoor activities. For more detailed weather information, check out La Fortuna weather in December.
As September blankets La Fortuna, visitors can expect a unique blend of tropical warmth and abundant rainfall. With an average temperature hovering comfortably around 24°C (76°F), the days are often warm, yet the near-constant humidity of 80% may create a pleasantly sweltering atmosphere. This month stands out for its significant rainfall, with nearly every day witnessing some showers, transforming the lush landscape into a vibrant wonderland. While other months see less precipitation, September invites travelers to embrace the refreshing beauty of the tropics under a canopy of rain-soaked greenery. For more insights into the region's weather patterns, explore La Fortuna Climate.