September Weather in Itoigawa, Japan

Last updated: August 21, 2025

September in Itoigawa, Japan presents a delightful mix of warm temperatures and vibrant rainfall. During this month, maximum temperatures can reach up to 32°C (90°F), while the average temperature sits at a comfortable 22°C (72°F), and the mercury dips as low as 13°C (56°F) at night. Rainfall is significant, totaling 265 mm (10.4 in) across 21 days, contributing to the region’s lush landscapes. Coupled with an humidity level of 89%, the atmosphere feels refreshing yet somewhat tropical, creating a unique ambiance that characterizes Itoigawa during this transition from summer to autumn.

September Temperature in Itoigawa

In September, Itoigawa experiences a delightful transition as summer gives way to autumn. The temperatures begin to cool slightly, with minimums averaging around 13°C (56°F), while daytime highs can reach a warm 32°C (90°F). This month boasts a pleasant average temperature of 22°C (72°F), making it a comfortable time for outdoor activities and exploring the vibrant autumn foliage. As September progresses, you can feel a refreshing shift in the air, hinting at the crisp, cooler months ahead. It's a perfect blend of warmth and the early onset of fall, creating a charming atmosphere ideal for visitors and locals alike.

September Weather in Itoigawa: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Itoigawa, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Itoigawa, September typically has an average temperature of {2}°C ({3}°F), with highs reaching up to {4}°C ({5}°F) and lows dropping to around {6}°C ({7}°F).
JanFebMarAprMayJunJulAugSepOctNovDec353541495966757871625140
Data source: Temperature data for Itoigawa generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Itoigawa

In September, Itoigawa experiences a notable continuation of the heavy rains typical of the late summer months, with precipitation measuring 265 mm (10.4 in), mirroring August’s totals. This period is characterized by 21 rainy days, making it one of the wetter months of the year. The trend reveals a gradual decline in rainfall from the peak of 347 mm (13.7 in) in July, yet the consistent precipitation in both August and September underscores the area’s vulnerability to lingering moisture as the seasons shift. As the autumn approaches, the average rainfall begins to taper, setting the stage for October's substantial yet slightly reduced average of 258 mm (10.2 in).

September Precipitation Trends in Itoigawa

The chart displays monthly precipitation patterns in Itoigawa, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Itoigawa, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec264235175174138168347265265258185294
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Itoigawa

September in Itoigawa, Japan, witnesses a notable shift in humidity, registering at 89%, which reflects the lingering warmth of summer while signaling the approach of autumn. This month acts as a transitional bridge, with humidity slightly lower than the peak levels of 92% seen in July and August, yet still comfortably above the year’s average of 86%. As the seasons change, September's humidity creates a unique ambiance—lush and vibrant, where the air is thick with the promise of autumn foliage. With a gradual decrease from the sweltering summer months, Itoigawa's September serves as a reminder of nature's cyclical dance, inviting both locals and visitors to savor the last whispers of warmth before the cooler days set in.

September Average Humidity in Itoigawa

This chart illustrates the average monthly humidity levels in Itoigawa, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Itoigawa is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%87%81%79%81%88%92%92%89%87%85%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Itoigawa

As September rolls in, Itoigawa, Japan, experiences a UV Index of 9, categorizing it under the very high exposure level. This marks a slight decrease from the peak summer months of July and August, when the index reached 11 and posed an extreme risk for sunburn with only 10 minutes of safe exposure time. However, September still demands caution, as the 15-minute burn time indicates that protective measures are essential for outdoor activities. This trend highlights the intense sunshine that characterizes the late summer period leading into autumn. To stay informed and safe, check out the full details at Itoigawa UV Index.

Maximum UV Index Levels in Itoigawa for September

The chart shows the monthly maximum UV Index (UVI) for Itoigawa in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Itoigawa typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3579101011119653
Data source: Itoigawa September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

September Sunshine in Itoigawa

In Itoigawa, Japan, September marks a delightful transition, with the sun gracing the region for 252 hours throughout the month. This follows a lively summer, where August peaked at 302 hours of sunshine, showcasing the vibrant warmth of the season. As summer slowly gives way to autumn, the sunlight begins to wane, but September still offers a generous amount of bright days, contributing to the lush landscapes that define this picturesque locale. Interestingly, the hours of sunshine this month remain significant compared to earlier months, with a noticeable increase from January's modest 148 hours. The trend indicates that while the sunny embrace of summer is fading, September retains a radiant charm, welcoming the rich colors of autumn without diminishing its brightness.

Monthly Sunshine Duration in Itoigawa: September Highlighted

The September sunshine duration represents the total number of hours Itoigawa experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec148h204h259h280h303h297h286h302h252h227h216h192h
Data source: Itoigawa September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Itoigawa During September

In Itoigawa, Japan, the likelihood of sunny weather sees a noticeable shift throughout the year, with September offering a 32% chance of sunshine. This marks a slight increase from the summer months, where July and August experience a dip in sunny days, at 36% and 21% respectively. As the season transitions into autumn, September reflects a moderate balance between sun and clouds, nestled between the higher chances of sun experienced in April and October, which boasts a 39% likelihood. This trend highlights September as a transitional month, where the fading warmth still holds promise for clear skies, making it a wonderful time to enjoy the natural beauty of the region.

Percentage of Sunny Days in September in Itoigawa

The chart illustrates the percentage of sunny days in Itoigawa throughout the year, with September highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Itoigawa experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec22%31%32%45%31%28%36%22%32%39%46%27%
Data source: Itoigawa September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Itoigawa in September

In Itoigawa, Japan, September marks a graceful transition from the vibrant, long days of summer to the cooler embrace of autumn. With 12 hours of daylight, the month captures the essence of early fall, showcasing a decrease from the peak of 14 hours in June, July, and August. This gradual decline reflects a natural rhythm, as daylight begins to shorten in anticipation of the coming colder months. Following the lively summer, October will further reduce daylight to 11 hours, prompting a shift in both nature and human activity as the region prepares for winter's arrival. The ebb and flow of daylight in this coastal city beautifully encapsulates the changing seasons, inviting residents and visitors alike to savor each moment as the landscape transforms.

Average Daylight Hours in Itoigawa for September

The chart illustrates the variation in daylight duration in Itoigawa throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 55m10h 48m11h 57m13h 8m14h 8m14h 38m14h 23m13h 31m12h 23m11h 12m10h 10m9h 39m
Data source: Itoigawa daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Itoigawa

As summer transitions into autumn, September in Itoigawa, Japan, greets residents with its gentle breezes. With an average wind speed of 1.9 m/s (4 mph), September mirrors the calmness of its predecessor, August. This period marks a noticeable dip in wind speeds compared to the brisk gusts of earlier months, such as January and November, where averages range from 3.3 to 3.9 m/s. The consistency in low wind speeds during late summer and early autumn creates a serene atmosphere, perfect for outdoor activities and enjoying the beautiful scenery that surrounds this charming coastal city. As the year progresses, Itoigawa's winds will gradually pick up again, hinting at the dynamic seasonal shifts to come.

Average September Wind Speed in Itoigawa

The chart displays monthly wind speed patterns in Itoigawa, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec3.43.92.52.52.71.61.61.91.9 m/s2.33.33.7
Data source: Itoigawa September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Itoigawa Compares to Other Months

Weather in Itoigawa varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Itoigawa, focusing on differences in temperature, rainfall, humidity, and UV levels.

In September, the weather in Itoigawa is notably warmer, with average temperatures ranging from a mild 22°C (72°F) to a maximum of 32°C (90°F). The month also sees significant rainfall, accumulating to 265 mm (10.4 in) over 21 days, and high humidity levels at 89%. In contrast, January brings much colder temperatures, with averages plummeting to around 2°C (35°F) and a maximum of only 11°C (53°F). Despite a similar total precipitation of 263 mm (10.4 in) over 23 days, January’s chill is palpable, with humidity slightly lower at 88%. For more detailed information, you can check Itoigawa weather in January.

In September, the weather is generally warm, with temperatures ranging from a minimum of 13°C (56°F) to a maximum of 32°C (90°F), and an average temperature of 22°C (72°F). The month is characterized by high humidity at 89% and substantial precipitation of 265 mm (10.4 in) over 21 days. In contrast, February brings much cooler conditions, with temperatures dropping to a minimum of -6°C (22°F), averaging just 2°C (35°F) and reaching a maximum of 12°C (54°F). Although February sees slightly less precipitation at 235 mm (9.2 in) over 22 days, the humidity remains high at 86%. For a deeper dive into February's climate, visit Itoigawa weather in February.

September and March exhibit distinctly different weather patterns. In September, temperatures range from a mild 13°C (56°F) to a warm 32°C (90°F), with an average of 22°C (72°F). This month also sees substantial precipitation, amounting to 265 mm (10.4 in) over 21 days, and humidity levels are quite high at 89%. In contrast, March experiences much cooler temperatures, with a minimum of -4°C (24°F) and a maximum of 16°C (61°F), averaging only 5°C (41°F). Precipitation is lower in March, totaling 175 mm (6.9 in) over 18 days, and humidity is slightly less at 81%. For more detailed information, you can check Itoigawa weather in March.

September and April present markedly different weather patterns. In September, temperatures range from a minimum of 13°C (56°F) to a maximum of 32°C (90°F), creating a warm atmosphere with an average of 22°C (72°F). However, this month is also characterized by high humidity at 89% and substantial rainfall, totaling 265 mm (10.4 in) across 21 days. In contrast, April is much cooler, with temperatures fluctuating between -1°C (31°F) and a maximum of 21°C (70°F), averaging only 9°C (49°F). April experiences less rainfall, approximately 174 mm (6.9 in) over 15 days, and lower humidity at 78%. Thus, while September offers warm and humid conditions, April's chillier and drier climate marks the transition into spring. For more details, see Itoigawa weather in April.

September weather is notably warmer and more humid than May, with average temperatures reaching 22°C (72°F) compared to May's 15°C (59°F). While September can experience maximum temperatures up to 32°C (90°F), May only sees a peak of 26°C (79°F). Precipitation levels are also higher in September, with 265 mm (10.4 in) falling over 21 days, compared to May’s 138 mm (5.4 in) across 15 days. Despite September's increased rainfall, May maintains a slightly lower humidity, at 81% versus September's 89%. For more insights on May’s climate, check out Itoigawa weather in May.

September exhibits warmer temperatures compared to June, with averages peaking at 22°C (72°F) and high temperatures reaching 32°C (90°F), while June’s average is a cooler 19°C (66°F) and its maximum temperature caps at 26°C (80°F). Additionally, September experiences significantly more precipitation, with 265 mm (10.4 in) falling over 21 days, as opposed to June’s 168 mm (6.6 in) over just 13 days. Despite these differences, both months maintain high humidity levels, with September slightly higher at 89% and June at 88%. For more detailed insights into weather specifics for June, you can visit Itoigawa weather in June.

When comparing the weather of September and July, it’s evident that July tends to be warmer and slightly more humid. In July, temperatures range from a minimum of 18°C (64°F) to a maximum of 34°C (94°F), with an average of 24°C (75°F), while September sees a cooler minimum of 13°C (56°F) and a maximum of 32°C (90°F), averaging at 22°C (72°F). Additionally, July experiences more rainfall with a total of 347 mm (13.7 in) over 23 days, compared to September's 265 mm (10.4 in) spread across 21 days. Both months have high humidity levels, with July at 92% and September at 89%. For more detailed information on July weather, check out Itoigawa weather in July.

In comparing the weather between August and September, we can observe notable differences in temperature and humidity levels. August features higher minimum and average temperatures, with a minimum of 18°C (64°F) and an average of 26°C (78°F), while September cools down slightly, with a minimum of 13°C (56°F) and an average of 22°C (72°F). Although both months receive the same amount of precipitation at 265 mm (10.4 in), September experiences this rainfall over 21 days, compared to August's 20 days. Humidity levels also remain high, with September at 89% and August at 92%. For more detailed insights on July weather in this region, check the following link: Itoigawa weather in August.

September typically experiences warmer temperatures compared to October, with daily averages around 22°C (72°F) peaking at 32°C (90°F), while October sees a cooler average of 16°C (62°F) with a maximum of 28°C (82°F). Although both months have considerable rainfall, September has a slightly higher precipitation total of 265 mm (10.4 in) over 21 days, compared to 258 mm (10.2 in) over 18 days in October. Humidity levels are also high in both months, with September at 89% and October at 87%. For more detailed information on October's weather, you can refer to Itoigawa weather in October.

In September, the weather is characterized by warm temperatures, with averages around 22°C (72°F) and maximums reaching up to 32°C (90°F). However, this month also sees significant rainfall, with nearly 265 mm (10.4 in) of precipitation spread over 21 days, making the atmosphere quite humid at 89%. In contrast, November brings a marked drop in temperature, with averages falling to 11°C (51°F) and minimums dropping to 0°C (32°F). While there is less rainfall in November, totaling 185 mm (7.3 in) over 19 days, the humidity is slightly lower at 85%. For a more detailed view of November weather in the region, you can check Itoigawa weather in November.

September and December exhibit significantly different weather patterns in the region. In September, temperatures range from a mild minimum of 13°C (56°F) to a warm maximum of 32°C (90°F), with an average of 22°C (72°F). The month sees considerable rainfall, with 265 mm (10.4 in) spread over 21 days, and high humidity levels at 89%. In contrast, December brings a notable drop in temperature, with lows plunging to -4°C (26°F) and a more moderate maximum of 18°C (65°F), averaging around 4°C (40°F). Precipitation increases slightly to 294 mm (11.6 in) over 24 days, while humidity remains relatively high at 86%. For more detailed information, you can check Itoigawa weather in December.

Compare Itoigawa's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Itoigawa

As September unfolds in Itoigawa, the weather presents a transition from the sweltering summer to a cooler autumn ambiance. The month is characterized by warm days averaging 22°C and occasional peaks reaching up to 32°C, offering a pleasant escape from the peak summer heat. However, this warmth is often accompanied by significant humidity and increased precipitation, with rain gracing the city on 21 days throughout the month. This shift enhances the lush beauty of the region, making it a perfect time for those who appreciate nature's vibrancy. For more detailed insights on what to expect, check out the comprehensive guide at Itoigawa Climate.