Last updated: August 21, 2025
In Iwakuni, Japan, September showcases a transitional climate marked by warm temperatures and high humidity. The month experiences a maximum temperature of 33°C (92°F), with an average of 24°C (75°F), offering a pleasant autumnal warmth. However, cooler evenings drop to a minimum of 15°C (60°F), creating a comfortable range for outdoor activities. Rainfall is a significant feature, with total precipitation measuring 237 mm (9.3 in) over approximately 14 wet days, contributing to the region's lush landscapes. With humidity levels averaging 84%, the month also ushers in a vibrant atmosphere, ideal for immersing in Iwakuni's stunning natural beauty.
In September, Iwakuni experiences a delightful transition towards autumn, with temperatures showcasing a notable shift. The minimum temperature hovers around 15°C (60°F), rising comfortably to an average of 24°C (75°F) during the day, and peaking at a warm 33°C (92°F). This month marks a departure from the sweltering heat of summer, yet retains a pleasant warmth that invites outdoor activities. As the humidity begins to wane, the inviting climate sets the stage for enjoying the region's stunning scenery, making September a cherished time for both locals and visitors alike.
In September, Iwakuni experiences a significant amount of rainfall, with 237 mm (approximately 9.3 inches) recorded over 14 days. This downpour marks a slight decrease from the intense summer months of July and August but remains substantial within the yearly context. September's precipitation signals the transition into autumn, where moisture levels begin to taper off in the following months, notably in October when average rainfall drops to 172 mm. The pattern of frequent rainfall persists, reflecting the region's humid subtropical climate, balancing the heavy summer showers with the onset of cooler, wetter autumn days. This seasonal shift not only provides a refreshing reprieve but also plays a crucial role in supporting the rich biodiversity of the area.
September in Iwakuni, Japan, sees a notable humidity level of 84%, which reflects a slight decrease from the sweltering summer months. This month marks a transition from the peak humidity of 95% in July and 93% in August, ushering in more comfortable conditions as autumn approaches. While humidity remains relatively high compared to the cooler months ahead, September is a respite from the intense summer heat, indicating a gradual shift towards the drier air of October’s average 79%. Thus, as the year progresses, residents can anticipate a slow and welcome reduction in humidity, promoting a more enjoyable outdoor experience.
As September rolls in Iwakuni, Japan, the UV Index signals a shift in the summer glare, showing a very high reading of 10, which suggests a burn time of just 15 minutes for unprotected skin. This drop from the extreme levels seen in July and August highlights a gradual easing of harsh sun exposure, yet caution is still essential. As the seasons transition, individuals should remain vigilant—particularly as the UV Index expects to decrease to 7 in October. For insights on UV exposure trends throughout the year, explore more at Iwakuni UV Index.
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As summer wanes into fall, September in Iwakuni, Japan offers a delightful blend of warmth and sunshine, with an impressive 260 hours of sunlight. This marks a gentle dip from August's peak of 308 hours, yet still surpasses the early months of the year, indicating a seasonal transition that embraces the lingering warmth of summer. The sunshine begins to soften as October approaches, with 254 hours expected, but September’s inviting glow ensures that outdoor adventures remain splendid before autumn fully takes hold. The gradual decrease in daylight hours reflects a broader trend of diminishing sunlight as the year progresses, yet September proudly stands out as a vibrant close to summer, inviting both locals and visitors to bask in its gentle rays.
In Iwakuni, Japan, September brings a 31% chance of sunny weather, a slight increase compared to the summer months but still lower than the spring and fall. This transitional month marks the tail end of the rainy season, as the likelihood of sunshine begins to rise from the summer’s peak of cloudiness in July and August, both of which boast a mere 23% and 25%, respectively. As autumn approaches, the sunshine percentage notably improves, rising to 59% in October. While September may not guarantee endless blue skies, the gradual shift towards clearer weather suggests a promising outlook for those hoping to enjoy outdoor activities before the cooler temperatures set in.
As summer fades into autumn in Iwakuni, Japan, September brings a gentle transition in daylight duration, averaging 12 hours of daylight. After basking in the long 14-hour days of June and July, the daylight begins to recede, reflecting nature's shift towards the quieter months ahead. Following the peak summer light, days shorten slightly, maintaining a balance with the 13 hours observed in August, before continuing the gradual decline into October's 11 hours. This trend underscores a beautiful rhythm of seasonal change, inviting residents and visitors alike to enjoy the warm hues of early fall before the days grow shorter still.
As September arrives in Iwakuni, Japan, a gentle breeze caresses the landscape, with average wind speeds settling at around 2.3 m/s (5 mph). This slightly lower rate compared to the bustling summer months reflects a transition into the milder autumn season. While earlier months experienced a gradual lull with June seeing just 1.8 m/s (4 mph), September offers a refreshing change without the intensity of July and August. Striking a balance, the wind speeds remain consistent with October, hinting at the upcoming cooler temperatures. Overall, September's breeze provides a serene backdrop, inviting residents and visitors alike to savor the shifting seasons and the enchanting beauty of Iwakuni.
Weather in Iwakuni varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Iwakuni, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present strikingly different weather characteristics. In September, temperatures range from a mild 15°C (60°F) to a warm 33°C (92°F), with an average of 24°C (75°F). This month is marked by significant rainfall, totaling 237 mm (9.3 in) over 14 days, and high humidity at 84%. In contrast, January experiences much colder conditions, with temperatures dipping as low as -4°C (25°F) and reaching a maximum of only 15°C (59°F), averaging 5°C (42°F). Rainfall is minimal in January, accumulating to just 49 mm (1.9 in) over 6 days, accompanied by a lower humidity level of 76%. For more details about January weather in Iwakuni, check out Iwakuni weather in January.
September and February present stark contrasts in weather. September boasts warmer temperatures, with a range from a mild 15°C (60°F) at night to a sweltering 33°C (92°F) during the day, alongside high humidity levels of 84%. However, it also brings significant rainfall, averaging 237 mm (9.3 in) over about 14 days. In contrast, February experiences much cooler temperatures, with nighttime lows plunging to -4°C (26°F) and daytime highs reaching only up to 20°C (68°F). Precipitation is less frequent in February, totaling 69 mm (2.7 in) over just 7 days, and the humidity is relatively lower at 72%. For more detailed insights, check out Iwakuni weather in February.
In September, the weather is notably warmer with temperatures ranging from a minimum of 15°C (60°F) to a maximum of 33°C (92°F), accompanied by high humidity levels at 84%. This month experiences significant rainfall, with approximately 237 mm (9.3 in) over about 14 days. In contrast, March sees much cooler temperatures, peaking at 22°C (71°F) with a minimum of 1°C (33°F) and an average of 10°C (50°F). Precipitation is also lower, totaling around 125 mm (4.9 in) across 10 days, and the humidity is a brisk 69%. For more insights, you can check Iwakuni weather in March.
In September, the weather tends to be much warmer than in April, with temperatures ranging from a minimum of 15°C (60°F) to a maximum of 33°C (92°F), and an average of 24°C (75°F). This month also experiences higher humidity at 84% and significant rainfall, totaling 237 mm (9.3 in) over about 14 days. In contrast, April sees cooler temperatures, with a minimum of 2°C (36°F), an average of 14°C (58°F), and a maximum of 24°C (76°F). The precipitation in April is lower, at 137 mm (5.4 in), falling over approximately 9 days and accompanied by a more comfortable humidity level of 75%. For more details, you can check Iwakuni weather in April.
When comparing the weather in September and May, notable differences emerge in temperature and precipitation patterns. September boasts warmer temperatures, with lows around 15°C (60°F), averaging 24°C (75°F), and highs reaching up to 33°C (92°F). In contrast, May experiences cooler conditions, with a minimum temperature of 7°C (45°F), an average of 19°C (66°F), and a maximum of 28°C (83°F). Additionally, September sees more rainfall, accumulating 237 mm (9.3 in) over 14 days, compared to May's 136 mm (5.4 in) over just 9 days. Interestingly, both months share the same humidity level of 84%. For more details on May weather, you can refer to Iwakuni weather in May.
When comparing the weather in September and June, September tends to be warmer, with average temperatures reaching 24°C (75°F), peaking at 33°C (92°F), while June averages at 22°C (72°F) with a maximum of 29°C (85°F). Both months experience a similar frequency of rainfall, with precipitation occurring on about 14 days in each month. However, September sees a higher total precipitation of 237 mm (9.3 in) compared to June's 181 mm (7.1 in). Humidity is slightly lower in September at 84%, contrasting with June's higher level at 88%. For a more detailed look at June weather, you can visit Iwakuni weather in June.
In comparing the weather conditions of September and July, September tends to be slightly cooler with average temperatures ranging from a minimum of 15°C (60°F) to a maximum of around 33°C (92°F), while July has higher averages, starting at 18°C (65°F) and peaking at 35°C (95°F). Additionally, July experiences higher humidity levels at 95% compared to September's 84%, contributing to a more muggy atmosphere. Precipitation is also greater in July, totaling 386 mm (15.2 in) over 19 days, whereas September sees 237 mm (9.3 in) over 14 days. For a more detailed look at July's weather patterns, you can refer to Iwakuni weather in July.
September weather in Iwakuni features a slightly cooler temperature range compared to August, with minimums of 15°C (60°F) and maximums reaching 33°C (92°F), resulting in an average temperature of 24°C (75°F). In contrast, August experiences warmer temperatures, with minimums around 20°C (67°F) and maximums peaking at 35°C (96°F), giving it a higher average of 28°C (82°F). Precipitation in September totals 237 mm (9.3 in) with rain over 14 days, while August has a slightly higher precipitation level of 256 mm (10.1 in), also spread across 14 days. Humidity is higher in August at 93%, compared to September’s 84%. For more detailed insights about August weather, you can visit Iwakuni weather in August.
September tends to be warmer and more humid compared to October, with average temperatures ranging from a minimum of 15°C (60°F) to a maximum of 33°C (92°F) and an average of 24°C (75°F). The month also experiences significant rainfall, totaling 237 mm (9.3 in) across 14 days, contributing to a high humidity level of 84%. In contrast, October sees a drop in temperature with minimums of 8°C (46°F) and average highs of 29°C (85°F), leading to a cooler and more comfortable climate overall. Precipitation decreases to 172 mm (6.8 in) over 10 days, and humidity levels also decline to 79%. For more information on October weather, you can check Iwakuni weather in October.
September typically brings warmer temperatures, with average highs reaching up to 33°C (92°F) and a high humidity level of 84%. The month experiences considerable rainfall, with 237 mm (9.3 in) over about 14 days, creating a muggy atmosphere. In contrast, November showcases a significant drop in temperature, with averages around 13°C (55°F) and maximums peaking at 23°C (74°F). This month is characterized by much lower precipitation, totaling just 37 mm (1.5 in) over 5 days, alongside slightly reduced humidity at 76%. For more details, you can check out Iwakuni weather in November.
September and December exhibit contrasting weather conditions. In September, temperatures are notably warmer, ranging from a minimum of 15°C (60°F) to a maximum of 33°C (92°F), with an average temperature of 24°C (75°F). The month also sees significant rainfall, with 237 mm (9.3 in) of precipitation over 14 days and a high humidity level of 84%. In sharp contrast, December experiences much cooler temperatures, with a minimum of -1°C (31°F) and a maximum of 20°C (69°F), averaging at 7°C (46°F). Precipitation drops to 61 mm (2.4 in) over just 6 days, and humidity decreases to 75%. For more detailed information, you can check Iwakuni weather in December.
As September rolls in, Iwakuni experiences a striking transition in weather, characterized by warm temperatures and increased humidity. While the heat persists, reaching a sweltering peak of 33°C, the average cools down to a more comfortable 24°C, offering relief from the summer's intensity. However, with approximately 237 mm of rainfall over 14 days, it's clear that September stands out with its heightened chances of precipitation, making it one of the wettest months of the year. For a deeper understanding of the overall climate patterns in this beautiful region, visit Iwakuni Climate.