September Weather in Sapporo, Japan

Last updated: August 21, 2025

In Sapporo, Japan, September ushers in a transitional climate characterized by a maximum temperature reaching 29°C (84°F), an average of 17°C (63°F), and a minimum of 4°C (40°F). This month experiences significant precipitation, with 126 mm (5.0 in) spread across approximately 14 days, contributing to the city’s lush landscapes. The humidity remains elevated at 88%, creating a distinct atmosphere that captures the essence of early autumn. Visitors should prepare for fluctuating conditions, making it an ideal time to explore the city’s vibrant outdoor activities amid the changing foliage.

September Temperature in Sapporo

In September, Sapporo begins to transition from the warmth of summer to the cool embrace of autumn. With minimum temperatures settling around 4°C (40°F) and an average high reaching up to 29°C (84°F), the city experiences a pleasant and comfortable climate that enticingly invites outdoor activities. This month marks a notable drop from the sweltering summer days of August, where highs also hovered around 31°C (88°F). As the month progresses, the delightful average temperature of 17°C (63°F) signals a refreshing change, making it an ideal time for locals and travelers to enjoy the stunning autumn foliage.

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

The chart illustrates September temperature patterns in Sapporo, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sapporo, 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).
JanFebMarAprMayJunJulAugSepOctNovDec212232415359686963513926
Data source: Temperature data for Sapporo 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 Sapporo

In September, Sapporo experiences a significant uptick in precipitation, with an average of 126 mm (5.0 in) of rainfall spread over 14 days. This marks a decline from the heavier August rains, which see 183 mm (7.2 in), but still falls within the wet season's pattern. The consistent moisture in September suggests a transitional period as the city shifts from summer to autumn, maintaining a lush landscape. Interestingly, the rain levels in September are slightly higher than those in both October and November, indicating that while the leaves may begin to change color, the skies above remain abundant with moisture, setting the stage for the autumn months ahead.

September Precipitation Trends in Sapporo

The chart displays monthly precipitation patterns in Sapporo, 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 Sapporo, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec566386879412311318312612011779
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Sapporo

In September, Sapporo experiences a notable shift in humidity, averaging 88% as summer begins to fade. This month marks a decline from the peak levels noted in August, which boasts an impressive 95% humidity. Following the sweltering heat of July and August, with their record highs of 93% and 95%, September brings a more soothing climate, yet still retains a substantial level of moisture in the air. The consistent humidity from May to September showcases the region's warm, humid summers, but as autumn approaches, the trend shifts towards drier conditions, evident in the October dip to 83%. Overall, September serves as a transitional month, bridging the intense summer humidity and the more moderate conditions to come.

September Average Humidity in Sapporo

This chart illustrates the average monthly humidity levels in Sapporo, 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 Sapporo is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%83%81%81%86%87%93%95%88%83%79%80%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Sapporo

In September, Sapporo, Japan experiences a very high UV Index of 8, indicating a need for sun protection to avoid harmful effects from prolonged exposure. This month marks a slight decrease from the peak of 10 seen in August, yet it still demands caution, with a burn time of only 15 minutes for those sensitive to UV rays. Following a summer of heightened UV levels (with consistent readings of 9 in June, July, and much of August), the trend shows that while the intensity begins to taper off heading into autumn, precautions remain essential. Whether you're exploring the city or enjoying the stunning scenery, staying informed about the UV Index is crucial for safe outdoor activities. For more detailed information, visit Sapporo UV Index.

Maximum UV Index Levels in Sapporo for September

The chart shows the monthly maximum UV Index (UVI) for Sapporo 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 Sapporo typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2367999108532
Data source: Sapporo 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 Sapporo

As September rolls into Sapporo, a gentle shift in the daylight hours complements the onset of autumn. With 269 hours of sunshine, this month captures a vibrant essence, reflecting a gradual decline from July's peak of 321 hours. Visitors can bask in the warmth of early fall, appreciating how September bridges the long, sun-filled days of summer to the crisp, shorter days of October, which sees a drop to 234 hours. The transition showcases an enchanting blend of hues as leaves turn, while the diminishing sunlight creates an inviting ambiance perfect for exploration. In Sapporo, September invites you to relish the lingering warmth before the chill of winter sets in, making it a splendid time to experience the city’s beauty.

Monthly Sunshine Duration in Sapporo: September Highlighted

The September sunshine duration represents the total number of hours Sapporo 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.
JanFebMarAprMayJunJulAugSepOctNovDec133h189h243h287h309h297h321h292h269h234h177h163h
Data source: Sapporo September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Sapporo During September

In Sapporo, Japan, the likelihood of sunny weather in September stands at 32%, suggesting a moderately bright outlook as summer transitions into autumn. This small uptick from the summer months, coupled with a notable 42% chance of sun in June and a slight dip to 28% in August, indicates that while September may not boast the sunniest days of the year, it still offers opportunities for pleasant weather. Interestingly, as the year progresses, the chances remain fairly stable with October and November also around 32%, hinting at a consistent climate pattern as the region shifts into cooler months. Thus, September serves as a refreshing bridge to autumn, with just enough sunny breaks to enjoy the changing leaves and crisp air.

Percentage of Sunny Days in September in Sapporo

The chart illustrates the percentage of sunny days in Sapporo 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 Sapporo experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec29%25%35%40%24%42%39%28%32%32%35%32%
Data source: Sapporo September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Sapporo in September

As September unfolds in Sapporo, Japan, the days gradually begin to shorten after the vibrant summer months. With approximately 12 hours of daylight, this transitional period marks a gentle decline from the sun-soaked days of August, which enjoyed 13 hours. The increase in daylight from the winter months, where January and November linger at only 9 hours, exemplifies the dynamic seasonal shifts in this northern locale. As autumn approaches, Sapporo prepares to embrace the changing scenery, basking in the warm hues of early fall before the shorter, darker days of winter set in.

Average Daylight Hours in Sapporo for September

The chart illustrates the variation in daylight duration in Sapporo throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 23m10h 30m11h 56m13h 24m14h 39m15h 17m14h 58m13h 52m12h 28m11h9h 43m9h 2m
Data source: Sapporo daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Sapporo

As September rolls into Sapporo, Japan, the gentle whispers of the wind begin to shift, with an average speed of 2.5 m/s (6 mph). This slight increase from the summer's calm breezes marks a transition, hinting at the impending autumn. Throughout the year, the wind tends to be at its lightest during the warmer months of June, July, and August, averaging around 2.3 m/s (5 mph). However, as autumn approaches, wind speeds gradually increase, reflecting nature’s shift. The breeze in September not only carries a hint of cooler air but also sets the stage for the crisp, vibrant days ahead, as October sees a further rise to 2.6 m/s (6 mph) before winter’s arrival. This subtle fluctuation in winds underscores the seasonal rhythms that define Sapporo's enchanting climate.

Average September Wind Speed in Sapporo

The chart displays monthly wind speed patterns in Sapporo, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.93.12.93.32.92.32.42.32.5 m/s2.62.93.0
Data source: Sapporo September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Sapporo Compares to Other Months

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

September and January present contrasting weather patterns, showcasing the shift from warm to cold climates. In September, temperatures range from a mild 4°C (40°F) at night to a warm 29°C (84°F) during the day, with an average of 17°C (63°F). The month sees considerable rainfall, accumulating 126 mm (5.0 in) over 14 days, contributing to a high humidity level of 88%. In stark contrast, January brings frigid conditions, with temperatures plunging to a minimum of -19°C (-2°F) and reaching a maximum of only 4°C (40°F), averaging -6°C (21°F). Precipitation is lower at 56 mm (2.2 in) over 13 days, and humidity stands at 84%. The two months exemplify the dramatic seasonal transition in Sapporo. For more detailed insights, you can refer to Sapporo weather in January.

The weather in September presents a much warmer and more humid climate compared to February. In September, temperatures range from a minimum of 4°C (40°F) to a maximum of 29°C (84°F), with an average of 17°C (63°F), and the humidity is notably high at 88%. The month sees an average of 126 mm (5.0 in) of precipitation over 14 days. In contrast, February is characterized by much colder conditions, with temperatures dropping as low as -17°C (2°F) and peaking at just 5°C (42°F), averaging around -5°C (23°F). It experiences a lower total precipitation of 63 mm (2.5 in) over 18 days, while humidity remains relatively low at 83%. For more detailed information, you can check Sapporo weather in February.

September and March present strikingly different weather conditions. In September, temperatures range from a pleasant 4°C (40°F) at night to a warm 29°C (84°F) during the day, with an average of 17°C (63°F). The month brings significant rainfall, with 126 mm (5.0 in) spread across 14 days, contributing to a high humidity level of 88%. In contrast, March sees much colder temperatures, with nighttime lows plunging to -13°C (9°F) and daytime highs reaching only 14°C (58°F), averaging around 0°C (32°F). Although March receives less precipitation at 86 mm (3.4 in) over the same number of days, the humidity is slightly lower at 81%. For more detailed insights into the March weather, you can explore Sapporo weather in March.

In comparison to September, April tends to be much cooler, with minimum temperatures dropping to -6°C (21°F) versus September's minimum of 4°C (40°F). The average temperature in April is significantly lower at 5°C (41°F), while September offers a more pleasant average of 17°C (63°F). Despite having slightly less precipitation, April still experiences rain on about 13 days, contributing to a total of 87 mm (3.4 in), compared to September’s 126 mm (5.0 in) over 14 days. Additionally, the humidity is somewhat lower in April at 81% compared to a muggy 88% in September, making the latter feel more oppressive. For more details, check out Sapporo weather in April.

In September, the weather is generally warmer, with average temperatures reaching up to 17°C (63°F) and maximums hitting 29°C (84°F), compared to May's average of 12°C (53°F) and a high of 30°C (87°F). September experiences more rainfall, with 126 mm (5.0 in) over 14 days, while May sees less precipitation at 94 mm (3.7 in) over 12 days. Humidity levels are similar, at 88% in September and 86% in May, creating a humid atmosphere in both months, but September's slightly higher moisture feels more pronounced during the transition to autumn. For more detailed insights, you can refer to Sapporo weather in May.

In comparing the weather of September and June, September tends to be slightly warmer overall, with average temperatures ranging from a minimum of 4°C (40°F) to a maximum of 29°C (84°F), whereas June has a narrower temperature range from 6°C (42°F) to 26°C (80°F). Both months experience similar levels of precipitation, with September receiving 126 mm (5.0 in) over 14 days compared to June's 123 mm (4.8 in) over 12 days. Humidity levels are also comparable, sitting at 88% in September and 87% in June. For a more detailed look at June weather in Sapporo, check out this link: Sapporo weather in June.

In comparing the weather between July and September, we find notable differences in temperature and humidity. July typically experiences warmer conditions, with minimum temperatures around 9°C (49°F) and average highs reaching 31°C (88°F). In contrast, September's temperatures range from a cooler minimum of 4°C (40°F) to a maximum of 29°C (84°F). While July has slightly less precipitation at 113 mm (4.5 in) over 12 days, September sees a bit more rainfall, accumulating 126 mm (5.0 in) across 14 days. Additionally, September presents slightly lower humidity levels at 88%, compared to July's 93%. For more detailed information about July's weather, you can check out Sapporo weather in July.

When comparing the weather in September to that of August, we see a noticeable shift in temperatures and precipitation patterns. September experiences a cooler range with a minimum of 4°C (40°F) and an average of 17°C (63°F), while August has milder temperatures, dropping no lower than 10°C (51°F) and averaging 21°C (69°F). The maximum temperatures also reflect this shift: September reaches up to 29°C (84°F), compared to August's peak of 31°C (88°F). In terms of precipitation, September receives 126 mm (5.0 in) over 14 days, which is less than August's 183 mm (7.2 in) during the same number of days. Additionally, humidity levels are slightly lower in September at 88%, whereas August sees a higher humidity level of 95%. For a detailed look at the August weather, you can visit Sapporo weather in August.

September and October present a noticeable shift in weather conditions. In September, temperatures range from a minimum of 4°C (40°F) to a maximum of 29°C (84°F), with an average of 17°C (63°F). The month experiences significant rainfall, totaling 126 mm (5.0 in) over about 14 days and high humidity at 88%. In contrast, October sees a drop in average temperatures to 11°C (52°F), with a minimum of -1°C (30°F) and a maximum of 24°C (76°F). While precipitation is slightly lower at 120 mm (4.7 in) across 17 days, humidity decreases to 83%, reflecting the transition into cooler autumn weather. For further insights into October's climate, check Sapporo weather in October.

September and November present stark contrasts in weather conditions. In September, temperatures range from a mild 4°C (40°F) at night to a warm 29°C (84°F) during the day, with an average temperature of 17°C (63°F). The month experiences relatively high humidity at 88% and substantial precipitation, totaling 126 mm (5.0 in) over 14 days. In contrast, November marks the transition to winter, with temperatures dropping significantly, with a minimum of -8°C (18°F) and a maximum of 17°C (62°F), resulting in an average of only 4°C (39°F). While November sees slightly less precipitation at 117 mm (4.6 in) over more days—20 in total—the humidity also decreases to 79%, creating a drier, colder atmosphere. For more detailed information, you can check Sapporo weather in November.

September weather is relatively mild, with temperatures ranging from a cool 4°C (40°F) to a warm 29°C (84°F), accompanied by high humidity at 88%. With an average precipitation of 126 mm (5.0 in) over 14 days, September experiences frequent rain. In contrast, December plunges into winter with much colder temperatures, averaging around -3°C (26°F) and dipping to a minimum of -15°C (6°F). Though December sees less precipitation overall at 78 mm (3.1 in), it is spread across more days, totaling 22. The humidity remains fairly high at 80%, but the chill transforms the landscape dramatically. For more details on December conditions, check out Sapporo weather in December.

Compare Sapporo's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Sapporo

As summer fades, September in Sapporo ushers in a refreshing change, with cooler temperatures and higher humidity that create a distinctly different atmosphere compared to the warmer months. This transitional period, marked by more frequent rainfall, as evident from the 14 days of precipitation, offers a unique charm as the city prepares for autumn. The maximum temperatures dip comfortably, making outdoor activities pleasant, while the vibrant landscapes come alive with seasonal color. To better understand how Sapporo's weather evolves throughout the year, explore the detailed insights in Sapporo Climate.