September Weather in Chichibu, Japan

Last updated: August 21, 2025

September in Chichibu, Japan brings a blend of warmth and moisture, making it an intriguing time to visit. With maximum temperatures soaring to 33°C (91°F) and an average of 20°C (69°F), the weather can be quite inviting. However, the month also sees significant precipitation, totaling 285 mm (11.2 in), spread across 24 days, contributing to the region's lush landscapes. Coupled with a high humidity level of 86%, this creates a unique atmospheric experience. Whether you're exploring the vibrant natural beauty or delving into local culture, Chichibu's September weather is as dynamic as its scenery.

September Temperature in Chichibu

In September, Chichibu experiences a delightful transition as summer gives way to early autumn. The temperatures begin to cool, yet remain comfortably warm, with average highs reaching around 33°C (91°F) and lows around 12°C (53°F). This month marks a notable shift from the sweltering heat of August, where highs soar above 35°C (94°F). The mild average temperature of 20°C (69°F) offers a pleasant respite for outdoor enthusiasts looking to explore the region's stunning landscapes. As the days become slightly shorter and cooler, September serves as the perfect backdrop for enjoying the vibrant fall foliage that Chichibu is renowned for, making it a captivating time to visit.

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

The chart illustrates September temperature patterns in Chichibu, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Chichibu, 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).
JanFebMarAprMayJunJulAugSepOctNovDec363845526266737668594940
Data source: Temperature data for Chichibu generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Chichibu

In September, Chichibu, Japan experiences a notable increase in precipitation, with a total of 285 mm (11.2 in) accumulated over 24 days. This marks a peak in the wet season, following the intense rainfall of July and August, but it also sets the stage for the upcoming October, which averages even higher at 359 mm (14.1 in). The rainfall in September contrasts sharply with the drier months of November and December, each receiving less than 60 mm, suggesting a significant shift as the region transitions from summer to autumn. The pattern of precipitation underscores September as a crucial time for replenishing local water sources, highlighting Chichibu's varied climatic rhythm throughout the year.

September Precipitation Trends in Chichibu

The chart displays monthly precipitation patterns in Chichibu, 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 Chichibu, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec55591521581862453772422853595957
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Chichibu

In September, Chichibu experiences a humidity level of 86%, continuing the trend of high humidity that peaks during the summer months. This figure reflects a slight drop from the sweltering averages of July and August, which hover around 93% and 90% respectively. Despite this decrease, September remains relatively humid compared to the earlier part of the year, where levels range from 70% to 76%. As the region transitions into autumn, the humidity—a key factor in its lush, verdant landscapes—gradually begins to ease, yet still retains a significant presence that shapes the local climate and lifestyle.

September Average Humidity in Chichibu

This chart illustrates the average monthly humidity levels in Chichibu, 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 Chichibu is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec76%74%70%74%82%88%93%90%86%83%80%78%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Chichibu

As September rolls into Chichibu, Japan, the UV Index registers at 10, placing it in the very high exposure category with a burn time of just 15 minutes. This marks a slight decline from the intense peaks of summer, yet caution is still essential. Throughout the year, Chichibu experiences notable fluctuations in UV exposure; for instance, the Index soared to a staggering 12 in July, indicating extreme conditions. As we transition from the summer months, the UV levels begin to stabilize, though September still demands vigilance, especially for outdoor enthusiasts. As you prepare for activities in this beautiful region, stay informed and protect your skin. For more detailed insights, visit Chichibu UV Index.

Maximum UV Index Levels in Chichibu for September

The chart shows the monthly maximum UV Index (UVI) for Chichibu 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 Chichibu typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec468101111121110754
Data source: Chichibu 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 Chichibu

September in Chichibu, Japan, offers a gentle transition from the vibrant summer sunshine, with the sun gracing the region for 226 hours. While this is a decline from the 276 hours enjoyed in August, it still reflects a healthy amount of daylight as autumn begins to settle in. As the year unfolds, the data reveals a fascinating trend where the hours of sunshine steadily rise from January’s start at 192 hours, peaking in May with 284 hours. Following the summer peak, the sunshine hours taper off, indicating a seasonal adjustment as Chichibu approaches the cooler months. This gradual shift creates a perfect backdrop for experiencing the breathtaking beauty of fall foliage, making September a delightful time to explore this picturesque part of Japan.

Monthly Sunshine Duration in Chichibu: September Highlighted

The September sunshine duration represents the total number of hours Chichibu 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.
JanFebMarAprMayJunJulAugSepOctNovDec192h236h262h279h284h262h228h276h226h206h230h235h
Data source: Chichibu September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Chichibu During September

In September, the likelihood of sunny weather in Chichibu, Japan, takes a dip, with only a 19% chance of clear skies. This figure is a sharp contrast to the sunnier months before and after, particularly the vibrant days of January and February, which boast chances of 59% and 71% respectively. As summer fades, the region experiences a notable decline in sunshine, following a trend of diminishing sunny days from spring through the summer months. By the time October arrives, the probability of sun begins to rebound to 45%, indicating that while September can be quite cloudy and rainy, the early autumn months soon offer a more favorable climate for outdoor activities.

Percentage of Sunny Days in September in Chichibu

The chart illustrates the percentage of sunny days in Chichibu 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 Chichibu experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec59%71%40%46%22%18%26%25%20%45%57%68%
Data source: Chichibu September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Chichibu in September

As summer winds down in Chichibu, Japan, September brings a gentle transition with about 12 hours of daylight. Following the peak summer months, where daylight stretched to a generous 14 hours, the reduction is a clear signal of the approaching autumn. The day length gradually diminishes as the year progresses, from a sunny 14 hours in June and July to a shorter 11 hours in October. This pattern reflects a rhythmic ebb and flow of daylight, with early spring witnessing a gradual increase as days lengthen from 10 hours in January and February to a blossoming 14 hours in May. Each month unfolds beautifully, carving a unique journey through light, warmth, and the cozy embrace of fall.

Average Daylight Hours in Chichibu for September

The chart illustrates the variation in daylight duration in Chichibu throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h10h 51m11h 57m13h 6m14h 4m14h 33m14h 18m13h 28m12h 22m11h 14m10h 15m9h 44m
Data source: Chichibu daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Chichibu

As September arrives in Chichibu, Japan, the wind settles into a gentle rhythm, with an average speed of just 1.3 m/s (3 mph). This marks a subtle decline from the summer months, where breezes were slightly stronger, yet the air remains refreshingly crisp. Observing the trend throughout the year, we notice a gradual easing of winds as the seasons transition from the more vibrant and lively gusts of January and February to the calm embrace of early autumn. While September’s winds are among the lightest of the year, they foster a serene atmosphere perfect for soaking in the rich colors of fall, inviting both residents and visitors to enjoy the tranquility that this charming region has to offer.

Average September Wind Speed in Chichibu

The chart displays monthly wind speed patterns in Chichibu, 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.
JanFebMarAprMayJunJulAugSepOctNovDec1.92.32.02.01.71.51.31.41.3 m/s1.71.72.0
Data source: Chichibu September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Chichibu Compares to Other Months

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

September and January present contrasting weather patterns. In September, temperatures range from a minimum of 12°C (53°F) to a maximum of 33°C (91°F), with an average of 20°C (69°F). This month is characterized by high humidity at 86% and significant rainfall, totaling 285 mm (11.2 in) over 24 days. In contrast, January is much colder, with temperatures dipping to a minimum of -12°C (10°F) and peaking at 16°C (61°F), averaging just 2°C (36°F). The precipitation is significantly lower in January at 55 mm (2.2 in) over 8 days, accompanied by a humidity level of 76%. For more insights, you can explore Chichibu weather in January.

September and February present stark contrasts in weather conditions. In September, temperatures range from a mild 12°C (53°F) to a hot 33°C (91°F), with an average of 20°C (69°F). However, this warm month also brings significant rainfall, totaling 285 mm (11.2 in) over 24 days, coupled with high humidity at 86%. In contrast, February is characterized by much colder temperatures, experiencing lows of -12°C (10°F) and highs reaching up to 21°C (70°F), with an average temperature of just 3°C (38°F). Precipitation in February is far less, at 59 mm (2.3 in) over 10 days, and humidity is lower at 74%. For a more detailed look at February weather, you can visit Chichibu weather in February.

In September, weather conditions are marked by relatively high temperatures, with a minimum of 12°C (53°F) and a maximum reaching 33°C (91°F), accompanied by high humidity levels at 86%. The month experiences significant precipitation, totaling 285 mm (11.2 in) over 24 days, making it a rather wet month. In stark contrast, March brings a cooler climate, with temperatures ranging from a minimum of -4°C (26°F) to a pleasant maximum of 24°C (76°F) and an average of 7°C (45°F). March typically sees lower precipitation, with 152 mm (6.0 in) over just 14 days and a lower humidity level of 70%. For a more detailed overview of March weather, you can refer to Chichibu weather in March.

When comparing the weather in September and April, one can observe significant differences in temperature and precipitation. September typically experiences warmer conditions, with an average temperature of 20°C (69°F) and peaks that can reach up to 33°C (91°F). In contrast, April has cooler temperatures, with average highs around 11°C (52°F) and maximums of 27°C (81°F). Precipitation levels in September are also higher, averaging 285 mm (11.2 in) over 24 days, compared to April's 158 mm (6.2 in) over just 16 days. Additionally, September has a higher humidity rate of 86%, compared to April's 74%. For more detailed insights, you can check Chichibu weather in April.

When comparing the weather in September and May, September tends to be warmer with average temperatures around 20°C (69°F), peaking at a high of 33°C (91°F), while May has a cooler average of 16°C (62°F) and can reach a maximum of 31°C (87°F). September experiences significantly more rainfall, with a total of 285 mm (11.2 in) spread over 24 days, compared to May's 186 mm (7.3 in) across 17 days. Additionally, humidity levels are slightly higher in September at 86%, compared to 81% in May. For more detailed insights on May weather, visit Chichibu weather in May.

In comparing the weather of September and June, both months exhibit warm temperatures, with September featuring a slightly higher average temperature of 20°C (69°F) compared to June's 19°C (67°F). September also records a higher maximum temperature of 33°C (91°F) versus June's 31°C (88°F). However, September sees more precipitation, totaling 285 mm (11.2 in) over 24 days, compared to June's 245 mm (9.7 in) over 21 days. Humidity levels are quite similar, with September at 86% and June slightly higher at 88%. For more detailed insights into June weather, you can check out Chichibu weather in June.

In comparing the weather between September and July, we see distinct differences in temperature and precipitation. In September, temperatures range from a minimum of 12°C (53°F) to a maximum of 33°C (91°F), with an average of 20°C (69°F). The month experiences substantial rainfall, accumulating 285 mm (11.2 in) over 24 days, and the humidity levels are high at 86%. In contrast, July boasts slightly warmer temperatures, with minimums around 15°C (59°F) and maximums reaching 34°C (93°F), averaging 23°C (74°F). It also has higher precipitation, totaling 377 mm (14.8 in) over 26 days, accompanied by even higher humidity at 93%. For more insights, you can check Chichibu weather in July.

September weather exhibits a slight cooling trend compared to August, with average temperatures dropping from 25°C (77°F) in August to 20°C (69°F) in September. While August experiences warmer highs of 35°C (94°F), September's maximum temperature reaches 33°C (91°F), signaling the onset of fall. Rainfall also increases in September, with 285 mm (11.2 in) over 24 days, compared to August's 242 mm (9.5 in) over 25 days. The humidity remains relatively high in both months, with September at 86% and August slightly higher at 90%. For more detailed weather information, you can visit Chichibu weather in August.

September's weather is characterized by warmer temperatures, with minimums around 12°C (53°F) and maximums reaching up to 33°C (91°F), while averaging a comfortable 20°C (69°F). The month is quite humid, with 86% humidity and significant precipitation of 285 mm (11.2 in) spread across 24 rainy days. In contrast, October sees a notable drop in temperatures, featuring a minimum of 4°C (40°F) and an average of 15°C (59°F), peaking at 30°C (86°F). Although October experiences even more precipitation at 359 mm (14.1 in) over 21 days, the overall humidity slightly decreases to 83%. For more details on October's conditions, you can check Chichibu weather in October.

September and November present notable contrasts in weather. In September, temperatures soar with a minimum of 12°C (53°F) and highs reaching up to 33°C (91°F), while the average sits at a warm 20°C (69°F). This month also sees significant rainfall, with 285 mm (11.2 in) spread across 24 days, coupled with high humidity levels of 86%. In stark contrast, November experiences much cooler temperatures, with a minimum dipping to -2°C (29°F) and an average of 10°C (49°F), whereas the maximum only reaches 21°C (70°F). Precipitation decreases sharply to 59 mm (2.3 in) over just 9 days, and humidity drops slightly to 80%. For more specific details about November weather, you can visit Chichibu weather in November.

September and December present stark contrasts in weather. September tends to be warm, with temperatures ranging from a minimum of 12°C (53°F) to a maximum of 33°C (91°F), and the month sees significant rainfall, averaging 285 mm over 24 days, coupled with high humidity at 86%. In contrast, December ushers in a much cooler climate, with temperatures dipping as low as -4°C (24°F) and averaging around 5°C (40°F). Precipitation in December is markedly lower, totaling only 57 mm over 8 days, with humidity decreasing to 78%. For more details on what to expect, check out Chichibu weather in December.

Compare Chichibu's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Chichibu

As summer transitions into autumn, September in Chichibu showcases a distinct shift in weather patterns, characterized by a blend of warmth and increased humidity. With an average temperature around 20°C, the days can still be quite hot, often reaching up to 33°C, but the nights offer a refreshing coolness that provides relief from the heat. This month is notably wet, with frequent rainfall across about 24 days, contributing to a total precipitation of 285 mm. The elevated humidity levels, typically around 86%, create a lush atmosphere, different from the drier conditions of the preceding months. For a comprehensive view of the changing seasons and how they shape the local environment, visit Chichibu Climate.