Last updated: August 21, 2025
In September, Hiroshima, Japan experiences a warm and humid climate, with maximum temperatures reaching up to 33°C (92°F) and an average temperature of 23°C (73°F). Morning and evening relief can be found in minimum temperatures that dip to 12°C (54°F). The city is also characterized by significant rainfall, accumulating around 230 mm (9.1 in) over approximately 14 days, contributing to a humidity level of 84%. Visitors should prepare for both heat and moisture, making it a month of vibrant weather transitions in this historic locale.
In Hiroshima during September, the weather showcases a delightful transition from the summer heat, with daily temperatures fluctuating between a minimum of 12°C (54°F) and a maximum of 33°C (92°F). The average temperature hovers around 23°C (73°F), striking a comfortable balance that invites both locals and visitors to enjoy the city's vibrant atmosphere. This month marks a gradual cooling trend from the sweltering peaks of August, which often see highs around the 36°C (97°F) mark. As autumn approaches, the pleasant conditions make September an ideal time to explore Hiroshima's rich history and beautiful landscapes, while still relishing the warmth of the waning summer sun.
September in Hiroshima marks a significant transition in the rainfall calendar, with 230 mm (about 9.1 inches) of precipitation falling over 14 days. Following the intense downpours of July, which recorded a staggering 391 mm (15.4 inches), September shows a noticeable decrease but still maintains a robust level of rainfall, indicative of the lingering summer monsoon influence. The month acts as a bridge, setting the stage for the tapering off of the heavy rains that characterize the preceding months. As the foliage begins to change, the consistent precipitation contributes to the lush landscapes, while the rain-soaked air signifies the slow arrival of autumn. This trend not only demonstrates Hiroshima's climatic shifts but also encapsulates the region's vibrant seasonal changes.
In September, Hiroshima experiences a notable dip in humidity, averaging at 84%, a slight decrease from the sweltering heights of 95% in July and 93% in August. This transition marks the end of the summer's oppressive moisture, perfectly aligning with the onset of autumn. Although humidity remains relatively high, it begins to trend downward as the crisp fall season approaches, offering a refreshing contrast to the sweltering summer months. The gradual decline underpins an overall pattern of fluctuating humidity levels throughout the year, with March experiencing the lowest levels at 69%. As the year progresses, late summer gives way to a more comfortable climate, making September a delightful time to enjoy the beauty of Hiroshima.
In September, Hiroshima experiences a very high UV Index of 10, indicating that sun safety precautions are essential during this time, with a burn time of just 15 minutes. This slight decrease from the extreme levels observed in the peak summer months of July and August (where both months hit a maximum UV Index of 12) signifies the gradual transition into autumn. However, with UV levels still significantly elevated compared to earlier months, such as January through June, it's crucial for residents and visitors alike to remain vigilant. Emphasizing sun protection remains vital, especially as this month bridges the gap before the UV Index begins to lower in October. For more details on sun exposure trends in the region, check out the Hiroshima UV Index.
UV Risk Categories
September in Hiroshima, Japan, is a captivating month marked by 260 hours of sunshine, elegantly nestled between the sun-soaked days of summer and the cooler autumn breeze. Following the height of August, which boasts a flourishing 308 hours of bright skies, September's sunshine begins to wane, offering a gentle transition to the changing seasons. The month's consistent brightness comes just after the vibrant spring and summer months, where April and May shine with 282 and 303 hours, respectively. As the days grow shorter, Hiroshima maintains a robust share of daylight, showcasing a rich tapestry of seasonal change that invites both reflection and exploration. This trend toward gradual decline fosters a cozy atmosphere, making September an ideal time to enjoy the city's natural beauty before the onset of winter’s embrace.
In Hiroshima, Japan, September brings a transition as the summer heat begins to wane, reflected in a 28% chance of sunny weather. This likelihood is a drop from the sunnier months of June through August, each hovering around the low 20s in terms of sunshine probability. Interestingly, September sits just above May's 30%, suggesting a trend of shifting weather patterns as autumn approaches. As the season changes, locals and visitors can expect moderate cloud cover, with sunny days becoming a refreshing rarity before the sunnier months of October and November, which boast probabilities of 56% and 50%, respectively. Embracing the beauty of early autumn while staying prepared for a mix of weather is key during this transitional month.
In September, daylight in Hiroshima gracefully begins its transition from the long, sunlit days of summer to the shorter days of autumn, offering approximately 12 hours of light. This marks a gradual decrease from the vibrant 14 hours in July and June, while still providing a warm, bright atmosphere for outdoor activities. As the days shorten, the rich tapestry of colors in nature prepares for the fall season, inviting locals and visitors alike to savor the lingering warmth before the daylight dips closer to 11 hours in October. Thus, September embodies a unique blend of summer’s farewell and autumn’s gentle embrace.
As summer fades into autumn, September winds in Hiroshima bring a gentle touch with an average speed of 2.1 m/s (5 mph). Although this is slightly less brisk than the preceding months, it is consistent with the trend of relatively mild breezes that characterize late summer and early autumn. The wind remains steady, providing a cool relief from the heat of August, yet not as strong as the gusts often seen in the winter months. Interestingly, September's calm winds echo the transition toward the cooler days ahead, creating an inviting atmosphere for both locals and visitors to enjoy the beauty of the city as it shifts into fall.
Weather in Hiroshima varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Hiroshima, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present contrasting weather patterns. In September, temperatures range from a mild 12°C (54°F) at night to a warm 33°C (92°F) during the day, with an average of 23°C (73°F). This month also sees significant rainfall, accumulating 230 mm (9.1 in) over about 14 days, and high humidity at 84%. In stark contrast, January experiences much colder conditions, with nighttime lows dipping to -7°C (20°F) and daytime highs reaching only 14°C (58°F), averaging around 4°C (39°F). Precipitation is significantly lower, at 54 mm (2.1 in) spread over 9 days, and humidity is somewhat less at 76%. For more detailed information about the weather in January, visit Hiroshima weather in January.
September and February present stark contrasts in weather conditions. September enjoys a warm average of 23°C (73°F), with maximum temperatures reaching up to 33°C (92°F). However, it also faces considerable rainfall, totaling 230 mm (9.1 in) over approximately 14 days, accompanied by high humidity of 84%. In contrast, February is much colder, with average temperatures around 5°C (41°F) and maximums only reaching 20°C (69°F). Precipitation in February is significantly lower at 67 mm (2.6 in) over about 9 days, and the humidity is also reduced to 72%. For more detailed insights, you can refer to Hiroshima weather in February.
In comparing the weather between September and March, there is a striking contrast in temperature and precipitation. September features a warm climate with temperatures ranging from a minimum of 12°C (54°F) to a maximum of 33°C (92°F), while March experiences much cooler conditions, with temperatures varying from -2°C (29°F) to a peak of 22°C (71°F). Precipitation is also more pronounced in September, totaling 230 mm (9.1 in) over 14 days, compared to March's 120 mm (4.7 in) over 12 days. Additionally, September’s humidity stands at 84%, making it feel even warmer, whereas March's humidity is lower at 69%. For more detailed insights, you can check Hiroshima weather in March.
In September, the weather is notably warmer with average temperatures ranging from a minimum of 12°C (54°F) to a maximum of 33°C (92°F), making it a time of lingering summer warmth. The month also experiences considerable precipitation, receiving about 230 mm (9.1 in) over approximately 14 days, accompanied by high humidity levels at 84%. In contrast, April features a cooler climate, where temperatures fluctuate between a chilly minimum of -1°C (31°F) and a pleasant maximum of 26°C (79°F). Precipitation is lower, totaling 128 mm (5.0 in) over about 9 days, with humidity at a more moderate 75%. For a closer look at the specific climate conditions during this time, you can visit Hiroshima weather in April.
In comparing the weather of September and May, we find notable differences in temperature and precipitation. September enjoys warmer temperatures, with a minimum of 12°C (54°F) and an average high of 33°C (92°F), while May starts cooler, with a minimum of 5°C (42°F) and an average maximum of 30°C (86°F). Precipitation is significantly higher in September, totaling 230 mm (9.1 in) over 14 days compared to May's 121 mm (4.8 in) over just 9 days. Both months share a high humidity level of 84%, contributing to a touch of mugginess in the air. For more detailed insights into May's climate, visit Hiroshima weather in May.
In comparing the weather between September and June, September tends to be slightly warmer with average temperatures reaching up to 23°C (73°F) compared to June's average of 21°C (71°F). Both months experience similar minimum temperatures, but September boasts a higher maximum temperature of 33°C (92°F) versus June's 30°C (87°F). Precipitation levels in September are significantly higher at 230 mm (9.1 in) over 14 days, compared to June's 177 mm (7.0 in) during the same number of days. Humidity remains relatively high in both months, with September at 84% and June at 88%. For more detailed information, you can check Hiroshima weather in June.
When comparing the weather in September and July, notable differences emerge. September features a broader temperature range with minimums around 12°C (54°F) and maximums reaching 33°C (92°F), averaging 23°C (73°F), while July maintains warmer temperatures with minimums of 17°C (64°F) and maximums peaking at 35°C (96°F), averaging 26°C (78°F). July experiences higher precipitation, with 391 mm (15.4 in) spread over 19 days compared to September’s 230 mm (9.1 in) over 14 days. Furthermore, humidity levels are more pronounced in July at 95%, whereas September has a slightly lower humidity level of 84%. For more details on July weather, you can check Hiroshima weather in July.
In comparing the weather conditions of September and August, September displays a cooler temperature range, with minimums dropping to 12°C (54°F) and maximums reaching 33°C (92°F), whereas August features notably warmer temperatures, with minimums at 17°C (63°F) and maximums soaring to 36°C (97°F). Precipitation levels are also slightly reduced in September, totaling 230 mm (9.1 in) compared to August’s 257 mm (10.1 in), though both months experience rain on 14 days. Additionally, September has a lower humidity average of 84%, in contrast to August’s higher humidity level of 93%, making September feel more comfortable overall. For a more detailed look at August weather, visit Hiroshima weather in August.
September and October present a notable shift in weather conditions. In September, temperatures range from a minimum of 12°C (54°F) to a maximum of 33°C (92°F), with an average of 23°C (73°F). The month also experiences significant rainfall, totaling 230 mm (9.1 in) over 14 days, coupled with high humidity at 84%.
In contrast, October brings cooler temperatures, with a minimum of 5°C (41°F) and a maximum of 28°C (84°F), averaging 17°C (63°F). The precipitation decreases to 164 mm (6.5 in) across 11 days, and humidity drops slightly to 79%. This transition reflects the onset of autumn, introducing milder weather and less rainfall. For more details, you can check Hiroshima weather in October.
September weather is characterized by warm temperatures, with averages around 23°C (73°F) and maximums reaching up to 33°C (92°F). This month also brings considerable rainfall, totaling 230 mm (9.1 in) over about 14 days, coupled with high humidity levels at 84%. In sharp contrast, November marks a notable drop in temperatures, where averages fall to 11°C (52°F), with minima plunging to -1°C (31°F) and a maximum of 23°C (75°F). Precipitation decreases significantly to 39 mm (1.5 in) over just 5 days, and humidity slightly dips to 76%. For more detailed information, visit Hiroshima weather in November.
September and December present contrasting weather conditions. In September, temperatures range from a mild 12°C (54°F) at night to a warm 33°C (92°F) during the day, with an average of 23°C (73°F). However, this month also experiences significant rainfall, totaling 230 mm (9.1 in) over 14 days, and high humidity levels at 84%. In stark contrast, December sees much cooler temperatures, with lows dropping to -2°C (28°F) and highs peaking at 20°C (68°F), averaging just 6°C (43°F). Precipitation in December is much lower, amounting to 66 mm (2.6 in) over 10 days, and humidity decreases to 75%. For more details on the weather conditions in December, check out Hiroshima weather in December.
As September unfolds in Hiroshima, the weather exhibits a distinctive shift that sets it apart from the earlier summer months. With maximum temperatures still reaching a warm 33°C, the average feel moves towards a more comfortable 23°C, signaling a transition that many welcome. However, this month also brings an increase in precipitation, with about 230 mm falling over 14 days, contributing to a notably humid atmosphere at 84%. This combination creates a dynamic weather experience, blending lingering summer warmth with the refreshing hints of autumn ahead. For a deeper dive into how Hiroshima's climate varies throughout the year, visit Hiroshima Climate.