Last updated: August 21, 2025
In September, Koshi, Japan experiences a vibrant transition into autumn, characterized by maximum temperatures soaring to 34°C (94°F) and a comfortable average of 24°C (76°F). As the month progresses, the minimum temperatures dip to a refreshing 12°C (53°F), offering a pleasant respite from the summer heat. However, visitors should prepare for the higher humidity levels at 84% and expect 184 mm (7.2 in) of rainfall over 14 days, making this month both lush and lively. Despite the occasional showers, the atmospheric charm of Koshi in September promises an enchanting experience amidst its natural beauty.
In Koshi, Japan, September marks a delightful transition as summer begins to give way to autumn. With a minimum temperature of 12°C (53°F) and an inviting average of 24°C (76°F), the month offers a refreshing reprieve from the sweltering heat of August, where temperatures often peak at 35°C (94°F). As the days grow shorter and the leaves hint at change, the maximum temperature reaches a comfortable 34°C (94°F), making it an ideal time for outdoor exploration. This period of mild weather is perfect for experiencing the vibrant local culture and stunning natural scenery, setting the stage for the cooler, crisper days that follow in October. Overall, September represents a harmonious blend of warmth and early autumn charm that captivates both residents and visitors alike.
In September, Koshi, Japan, experiences a marked shift in precipitation patterns, receiving 184 mm (7.2 in) of rain over 14 days. This amount represents a substantial decrease from the previous month's total of 277 mm, yet it still maintains a significant presence in the region's overall rainfall trends. As summer transitions into autumn, the rainfall begins to taper off, reflecting a natural decline after the peak of 478 mm in July. Interestingly, September's rainfall remains consistent with the earlier months of the year, falling above average when compared to the drier conditions observed in October and November. This gradual decrease in precipitation is indicative of the changing seasons, showcasing Koshi’s dynamic weather patterns.
In Koshi, Japan, September marks a notable shift in humidity levels as the summer warmth begins to wane. With humidity at a comfortable 84%, it reflects a decrease from the sweltering heights of 92% in July and 91% in August. This transition signals a gradual cool-down, bringing a welcome relief from the intense summer months. As autumn approaches, the humidity level remains relatively high when compared to the earlier winter months, such as January's 75% and February's 71%. This sticky summer-to-autumn shift fosters a unique atmosphere, where the remnants of summer linger just as the crispness of fall beckons. Overall, September in Koshi is characterized by a mellower humidity, making it a brief interlude before the cool, dry air of October sets in.
As summer gives way to autumn, September in Koshi, Japan, sees a UV Index of 11, maintaining its extreme exposure category from the previous months. This trend signifies a continued need for caution, as the burn time remains a swift 10 minutes for unprotected skin. Throughout the year, Koshi experiences fluctuating UV levels, peaking in July and August with a UV Index of 12, before slightly declining yet still presenting considerable risk in September. Awareness of these trends is crucial, as even as temperatures cool, the sun's intensity persists. For more information on the UV Index in Koshi, check out Koshi UV Index.
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September in Koshi, Japan, continues the trend of abundant sunshine, boasting 248 hours of sunlight, a slight dip following the peak of 294 hours in August. This vibrant month typically ushers in the early hints of autumn, with daylight still generous compared to the cooler winter months, which fall to around 218 hours in December. Following a gradual ascent from the year’s low of 178 hours in January, the sunlight hours display a clear trajectory of increasing brightness, peaking mid-summer before gently tapering off as the seasons change. As September transitions into October, the sunlight remains relatively stable, signaling the characteristic shifts of nature in this picturesque region.
In Koshi, Japan, September offers a modest 33% chance of sunny weather, positioning it as a transitional month as the summer heat begins to wane. This figure reflects a slight uptick in sunshine compared to the preceding months of July and August, which see a low of just 18% and 26% respectively. As the region shifts into autumn, this increase points to a gradual return of clearer skies, paving the way for more comfortable temperatures. Notably, October showcases a remarkable leap to 64%, indicating that while September may still feel somewhat unpredictable, it heralds the sunnier days to come.
As summer fades into autumn, September in Koshi, Japan, offers a gentle transition with 12 hours of daylight. Following the peak brightness of June and July—where days extended to 14 hours—the daylight begins to recede gradually. This decline continues into October, where the hours reduce further to 11. Interestingly, April to May showcases a notable increase in daylight, reflecting the vibrant energy of spring, while September marks the tail end of longer days, hinting at the cozy embrace of fall. Overall, the daylight duration in Koshi beautifully illustrates the rhythmic ebb and flow of seasons, inviting residents to enjoy the transforming landscape as nature prepares for the chill of winter.
In September, the gentle breeze of Koshi, Japan, reaches an average wind speed of 2.1 m/s (5 mph), signaling the transition into autumn. This slight dip follows the summer months, where the wind has maintained a steady 2.3 m/s, suggesting a subtle shift in the atmospheric conditions as the region prepares for cooler temperatures. Over the year, the wind speeds fluctuate modestly, with January's briskness at 2.5 m/s and June's calm retreating to 1.6 m/s. Yet, September's winds remain a reminder of nature's rhythm, as the patterns indicate a gentle breeze that complements the vibrant hues of changing leaves, creating a serene backdrop for reflection.
Weather in Koshi varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Koshi, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present stark contrasts in weather conditions. In September, temperatures range from a mild 12°C (53°F) at night to a scorching 34°C (94°F) during the day, with an average of 24°C (76°F). This month is characterized by high humidity at 84% and substantial rainfall, totaling 184 mm (7.2 in) over 14 days, making it quite a wet month.
In contrast, January offers a much colder experience, with temperatures dipping to a minimum of -5°C (24°F) and a maximum of 17°C (63°F), averaging just 6°C (42°F). Precipitation is significantly lower in January at 54 mm (2.1 in) across only 6 days, alongside a decrease in humidity to 75%. For more detailed insights into the January weather, you can visit Koshi weather in January.
September and February showcase a stark contrast in weather conditions. In September, temperatures range from a mild 12°C (53°F) to a sweltering 34°C (94°F), with an average of 24°C (76°F), accompanied by high humidity levels of 84%. This month also sees significant rainfall, totaling 184 mm (7.2 in) over about 14 days. In contrast, February experiences much cooler temperatures, with a minimum of -5°C (24°F) and a maximum reaching 20°C (69°F), averaging around 7°C (44°F). Precipitation is lighter in February, totaling 96 mm (3.8 in) over 10 days, and humidity drops to 71%. For a detailed look at February weather, you can check Koshi weather in February.
September and March present contrasting weather conditions. In September, temperatures range from a mild 12°C (53°F) at night to a sweltering 34°C (94°F) during the day, with an average temperature of 24°C (76°F). This month is marked by significant rainfall, averaging 184 mm (7.2 in) over 14 days and a high humidity level of 84%. In contrast, March experiences much cooler weather, with temperatures dipping as low as -1°C (30°F) at night and peaking at 24°C (75°F) during the day, resulting in an average of 11°C (52°F). There is less precipitation in March, totaling 131 mm (5.2 in) over 12 days and lower humidity at 71%. For a detailed look at this month, check out Koshi weather in March.
September and April present distinct weather patterns with notable differences in temperature and precipitation. In September, temperatures range from a minimum of 12°C (53°F) to a maximum of 34°C (94°F), averaging around 24°C (76°F). This month experiences considerable rainfall, with 184 mm (7.2 in) falling over 14 days and an average humidity of 84%. In contrast, April's temperatures are milder, with a minimum of 1°C (34°F) and a maximum of 28°C (82°F), yielding an average of 15°C (59°F). Rainfall in April is lighter, totaling 132 mm (5.2 in) over just 9 days, and humidity is slightly lower at 78%. For a closer look at April weather specifics, you can check out Koshi weather in April.
September and May offer distinct weather experiences, showcasing the transition between seasons. In September, temperatures range from a mild 12°C (53°F) at night to a warm 34°C (94°F) during the day, with an average of 24°C (76°F), while May's temperatures are cooler, with a minimum of 6°C (43°F), an average of 19°C (67°F), and a maximum of 30°C (86°F). Both months receive significant precipitation, with September seeing 184 mm (7.2 in) over 14 days and May slightly wetter at 213 mm (8.4 in) over 12 days. Interestingly, despite the difference in temperatures, humidity remains steady at 84% for both months, creating a humid atmosphere. For more specific insights on the weather in May, you can check Koshi weather in May.
In comparing the weather between September and June, we see some notable differences despite the months being relatively close in the calendar year. September boasts a slightly broader temperature range, with minimums around 12°C (53°F) and maximums reaching up to 34°C (94°F), resulting in an average temperature of 24°C (76°F). Conversely, June has a minimum temperature of 13°C (55°F) and tops out at 32°C (89°F), with an average of 23°C (73°F).
Additionally, September experiences 184 mm of precipitation over 14 days, while June is wetter, with 274 mm falling over 15 days. Humidity levels are quite similar for both months, with September at 84% and June slightly higher at 86%. For more specifics on June weather, you can refer to Koshi weather in June.
In comparing the weather between September and July, September tends to be slightly cooler, with temperatures ranging from a minimum of 12°C (53°F) to a maximum of 34°C (94°F), resulting in a comfortable average of 24°C (76°F). In contrast, July experiences warmer temperatures, where the minimum reaches 17°C (63°F) and the maximum can soar to 35°C (96°F), averaging 26°C (79°F). Rainfall is significantly higher in July, with 478 mm (18.8 in) over 20 days, compared to September’s 184 mm (7.2 in) over 14 days. Additionally, humidity levels in July are also higher at 92%, compared to September's 84%. For more detailed information, you can explore Koshi weather in July.
In comparing September and August weather, September tends to be cooler with an average temperature of 24°C (76°F), compared to August's warmer average of 28°C (82°F). While both months experience significant humidity, September's average humidity of 84% is slightly lower than August's 91%. Additionally, precipitation in September, at 184 mm (7.2 in) over 14 days, is less than August's 277 mm (10.9 in) over 15 days. For more detailed insights on August weather, you can check Koshi weather in August.
In September, the weather is notably warmer, with temperatures ranging from a minimum of 12°C (53°F) to a maximum of 34°C (94°F) and an average of 24°C (76°F). This month experiences higher precipitation levels of 184 mm (7.2 in) across 14 days, combined with high humidity at 84%. In contrast, October brings a noticeable drop in temperatures, with a minimum of 6°C (44°F), an average of 19°C (66°F), and a maximum of 31°C (88°F). Precipitation also decreases to 107 mm (4.2 in), occurring over just 8 days, while humidity remains similar at 83%. For a detailed look at October weather, check out Koshi weather in October.
September and November present a striking contrast in weather conditions. In September, temperatures soar with a minimum of 12°C (53°F) and an average high of 34°C (94°F), creating a warm and humid atmosphere with high humidity levels of 84%. This month also sees significant rainfall, with 184 mm (7.2 in) of precipitation over 14 days. In contrast, November experiences much cooler temperatures, with a low dropping to -1°C (30°F) and an average high of 25°C (77°F). Precipitation decreases significantly to 60 mm (2.4 in) across just 7 days, and humidity also lowers slightly to 81%. For a more detailed overview of November weather, you can check Koshi weather in November.
September and December present stark contrasts in weather conditions. In September, temperatures can soar as high as 34°C (94°F), with an average of 24°C (76°F) and a notable humidity of 84%. The month is characterized by considerable rainfall, accumulating to 184 mm (7.2 in) over about 14 days. In contrast, December brings much cooler weather, with maximum temperatures reaching only 22°C (72°F) and an average of just 7°C (45°F). The minimum temperatures even dip to -2°C (29°F). Precipitation during December is significantly lower at 71 mm (2.8 in) over about 7 days, and humidity decreases slightly to 79%. For more detailed information, you can visit Koshi weather in December.
As September rolls into Koshi, the weather takes on a distinct character, marked by warm temperatures and notable humidity. This month typically sees a blend of summer's warmth with an average temperature that invites both sunshine and occasional rain, leading to a total precipitation of 184 mm over about half the month’s days. With humidity levels soaring to 84%, the air feels quite muggy, setting it apart from the drier, cooler months that precede it. As nature prepares for the transition into autumn, September's weather is a reminder of the lingering summer vibes while also hinting at the cooler days to come. For more insights on the seasonal variations, explore Koshi Climate.