Last updated: August 21, 2025
September in Otaru, Japan offers a delightful transition into autumn, with maximum temperatures reaching around 26°C (80°F) and an average temperature of 18°C (65°F). Visitors can expect cooler evenings, as minimum temperatures dip to 10°C (50°F). The city experiences a moderate amount of rainfall, totalling 117 mm (4.6 in) over approximately 14 days, contributing to the strikingly lush landscapes. With humidity levels hovering around 88%, September's weather in Otaru creates a refreshing yet mildly damp atmosphere, making it an ideal time for exploring the enchanting scenery and rich culture of this coastal gem.
In September, Otaru, Japan transitions into a mild autumn, showcasing a pleasant climate that invites both locals and travelers to enjoy the changing scenery. With temperatures ranging from a minimum of 10°C (50°F) to a comfortable average of 18°C (65°F), the city experiences a gentle warmth, peaking at a delightful 26°C (80°F). This month marks a notable drop from the sweltering summer, offering a refreshing respite as the days become cooler. As nature begins its transformation, September's blend of crisp air and vibrant foliage provides the perfect backdrop for exploration and appreciation of Otaru's scenic beauty.
In September, Otaru, Japan, experiences a notable shift in precipitation patterns, recording 117 mm (4.6 inches) over 14 days. This amount marks a decrease from the heavy rains of August, which saw a staggering 169 mm (6.7 inches), but still remains relatively high compared to the earlier months of the year. The onset of autumn brings a moderate increase in rainfall, with October expected to climb even higher to 152 mm (6.0 inches). The trend reveals that as summer fades, the city embraces a season of increased precipitation, creating a lush, vibrant atmosphere that signals the arrival of fall in this picturesque coastal region.
In September, Otaru experiences a notable dip in humidity, averaging at 88%, a slight decrease from the peak summer months of July and August, which register an impressive 93% and 95%, respectively. This transition signifies the end of the humid summer season, as the air gradually begins to dry out heading into autumn. Interestingly, September's humidity remains relatively high compared to the months of early autumn, falling in line with the year’s general trend of elevated moisture during the warmer months. As temperatures cool down in October, the humidity further decreases to 83%, setting the stage for a more comfortable fall climate.
September in Otaru, Japan, sees a UV Index of 8, placing it in the very high exposure category and requiring precautions against sunburn, with a burn time of just 15 minutes. This month marks a slight decrease from the peak UV Index of 10 in August, yet it remains crucial for residents and visitors to protect themselves from intense UV radiation. As the summer wanes, the UV Index gradually declines from the highs of 9 earlier in the summer months of June through August, yet still demands attention during outdoor activities. For more detailed insights into UV exposure in Otaru throughout the year, be sure to check Otaru UV Index.
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As September unfolds in Otaru, Japan, it graces the city with an inviting 273 hours of sunshine, signaling the transition from the bustling summer to the more subdued autumn months. This vibrant shine, following the peak summer sunshine of 320 hours in July, reflects a gradual, yet steady decline that begins in August. Despite this decrease, September stands out as a month still rich in sunlight, brighter than the brisk October, which sees only 235 hours of sun. The lingering warmth of late summer makes September a charming time for visitors to explore Otaru’s scenic views, delightful festivals, and cultural treasures, all basking in the gentle glow of a setting sun, before the shorter, cloudier days of autumn take hold.
As September arrives in Otaru, Japan, residents and visitors can expect a 39% chance of sunny weather, marking a notable transition from the summer months. This percentage places September in a favorable position compared to the preceding months of June (48%) and July (47%), though it does experience a decline as autumn sets in, with August dropping to 33%. Interestingly, September's likelihood of sunshine is higher than both May (27%) and October (32%), suggesting that early fall still offers opportunities for pleasant, sun-drenched days. While not the sunniest month, September remains a promising time for outdoor activities and enjoying the scenic beauty of Otaru.
As September unfolds in Otaru, Japan, the transition from the vibrant summer days to the cooler embrace of autumn is reflected in the daylight duration, which offers approximately 12 hours of daylight. This marks a gentle decline from the peak of 15 hours experienced in June, showcasing the gradual shortening of days. Following the leisurely pace of summer, September provides a subtle shift, with daylight dipping just slightly more than an hour compared to August. The trend of decreasing daylight continues into October, emphasizing nature's rhythm as Otaru prepares for the winter months ahead. This gradual waning of daylight not only signals the arrival of fall but also invites residents and visitors alike to savor the beauty of the changing seasons.
As September rolls into Otaru, the gentler breezes of autumn begin to take hold, with the average wind speed settling at a calm 3.3 m/s (7 mph)—mirroring the light gusts of the preceding months of July and August. This transition signifies a noticeable decrease from the winter months, where winds often whipped through the city at higher velocities, peaking at 5.4 m/s (12 mph) in January and February. However, compared to earlier spring months like March and April, which saw transient gusts of around 4.1 m/s (9 mph), September holds onto a tranquil warmth, inviting locals and travelers alike to enjoy Otaru's picturesque scenery without the earlier chill. With October approaching, the wind speed is poised to pick up again, serving as a reminder of the changing seasons and the dynamic beauty of coastal Japan.
Weather in Otaru varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Otaru, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present a stark contrast in weather conditions. In September, temperatures range from a mild 10°C (50°F) during the night to a warm 26°C (80°F) during the day, with an average of 18°C (65°F). The month is characterized by high humidity at 88% and significant rainfall, totaling 117 mm (4.6 in) over 14 days. In contrast, January experiences much colder temperatures, with a minimum of -12°C (10°F) and a maximum of only 4°C (40°F), averaging -4°C (25°F). Despite receiving less precipitation at 87 mm (3.4 in), it occurs over more days, totaling 20, and the humidity is slightly lower at 84%. For a deeper insight into the frigid conditions of January, you can find more information Otaru weather in January.
When comparing the weather in September and February, stark contrasts emerge. September boasts a mild climate, with temperatures ranging from a minimum of 10°C (50°F) to a maximum of 26°C (80°F), while February experiences much colder conditions, with temperatures plummeting between -13°C (8°F) and 6°C (44°F). Additionally, September sees higher average temperatures of 18°C (65°F) and considerable humidity at 88%, contrasted by February’s average of -3°C (26°F) and slightly lower humidity at 83%. While both months experience precipitation, September has more rainfall over 14 days (117 mm or 4.6 in), whereas February has less with 99 mm (3.9 in) spread across 22 days. For more insights on February weather, you can check Otaru weather in February.
The weather in September is characterized by milder temperatures, with an average of 18°C (65°F) and highs reaching up to 26°C (80°F), making it a comfortable month. In contrast, March experiences much colder conditions, with average temperatures around 1°C (34°F) and maximums peaking at just 12°C (54°F). Precipitation is fairly comparable, with September receiving 117 mm (4.6 in) over 14 days, while March has 95 mm (3.7 in) across 16 days. Additionally, humidity levels are higher in September at 88%, compared to 81% in March. For more details about the weather during this chilly month, you can visit Otaru weather in March.
Comparing the weather in September and April reveals distinct differences in temperature and precipitation. In September, temperatures range from a minimum of 10°C (50°F) to a maximum of 26°C (80°F), with an average of 18°C (65°F). The month experiences a total of 117 mm (4.6 in) of precipitation over 14 days and has relatively high humidity at 88%. In contrast, April presents a much cooler climate, featuring temperatures that range from -3°C (26°F) to 17°C (63°F), with an average of just 5°C (40°F). This month sees less precipitation at 76 mm (3.0 in) over 11 days and lower humidity at 81%. For more detailed insights specific to April, you can refer to Otaru weather in April.
September and May present contrasting weather patterns despite sharing a maximum temperature of 26°C (80°F). In September, the average temperature is notably higher at 18°C (65°F) compared to May's cooler average of 11°C (51°F). Additionally, September sees more precipitation, with 117 mm (4.6 in) falling over 14 days, while May experiences less rain at 90 mm (3.6 in) over 13 days. Humidity levels are also slightly elevated in September at 88%, compared to May's 86%. For detailed information about the weather in May, check out Otaru weather in May.
In comparing the weather of September and June, September generally offers warmer temperatures, with averages around 18°C (65°F), while June has a cooler average of 14°C (58°F). The maximum temperatures in September can reach up to 26°C (80°F), as opposed to June’s maximum of 24°C (75°F). Precipitation levels are fairly similar, with September seeing 117 mm (4.6 in) across 14 days, compared to June's 112 mm (4.4 in) over 12 days. Both months experience high humidity, but September is slightly more humid at 88% compared to June's 87%. For more specific details about June weather, you can visit Otaru weather in June.
In comparing the weather patterns of September and July, several notable differences emerge. September tends to be slightly cooler, with temperatures ranging from a minimum of 10°C (50°F) to a maximum of 26°C (80°F), highlighting an average temperature of 18°C (65°F). In contrast, July enjoys milder conditions, featuring an average temperature of 20°C (68°F) with highs reaching up to 28°C (82°F). Additionally, September experiences higher precipitation levels, totaling 117 mm (4.6 in) over 14 days, compared to July's 101 mm (4.0 in) over 12 days. The humidity also plays a role, with September at 88% and July slightly higher at 93%, making July feel a bit more oppressive although still mild. For an in-depth look at July's weather specifics, you can visit Otaru weather in July.
In comparing the weather of September to August, September is noticeably cooler, with minimum temperatures dropping to 10°C (50°F) compared to August's 14°C (58°F). The average temperature in September is 18°C (65°F), while August maintains a warmer average of 21°C (70°F). Furthermore, September experiences less maximum heat, peaking at 26°C (80°F) versus August's 29°C (85°F). Although both months have precipitation on 14 days, September records less rainfall at 117 mm (4.6 in) compared to August's 169 mm (6.7 in), and slightly lower humidity levels—88% in September versus 95% in August. For more detailed information on August weather, you can visit Otaru weather in August.
In September, the weather is relatively warmer, with minimum temperatures around 10°C (50°F) and a maximum reaching 26°C (80°F). The month averages 18°C (65°F) and experiences substantial rainfall, totaling 117 mm (4.6 in) over approximately 14 days and a high humidity level of 88%. In contrast, October brings a noticeable chill, with minimum temperatures dropping to 4°C (39°F) and an average of 12°C (54°F). Although the maximum temperature can reach up to 22°C (71°F), October sees increased precipitation at 152 mm (6.0 in) over 17 days, albeit with lower humidity at 83%. For more detailed information, you can check Otaru weather in October.
September and November present significantly different weather patterns. In September, temperatures range from a mild 10°C (50°F) to a warm 26°C (80°F), with an average of 18°C (65°F). Although the month sees a relatively high humidity level of 88%, it has less rainfall compared to November, receiving 117 mm (4.6 in) over about 14 days.
In contrast, November experiences a sharp drop in temperatures, with minimums plummeting to -5°C (23°F) and a maximum of 15°C (59°F), averaging only 5°C (42°F). The month is also wetter, accumulating 167 mm (6.6 in) of precipitation over 22 days, but with lower humidity at 79%. For those interested in the specific conditions of November, you can find more details here: Otaru weather in November.
In September, the weather is notably milder, with temperatures ranging from a minimum of 10°C (50°F) to a maximum of 26°C (80°F) and an average of 18°C (65°F). However, it experiences significant rainfall, totaling 117 mm (4.6 in) over 14 days and high humidity at 88%. In contrast, December brings much colder conditions, where temperatures plunge to a minimum of -10°C (15°F) and only reach a maximum of 11°C (52°F) with an average of -2°C (29°F). Despite having higher total precipitation at 147 mm (5.8 in) spread over 27 days, December's humidity dips slightly to 80%. For more details, check out Otaru weather in December.
As summer bids farewell, September in Otaru brings a delightful transition characterized by mild temperatures and increased humidity, creating a cozy atmosphere throughout the month. With an average temperature of 18°C (65°F), it offers a refreshing change from the heat of the preceding months. However, this period also sees a rise in precipitation, with nearly half the month marked by rain, giving way to vibrant autumn foliage. While September may be wetter compared to the drier summer months, the overall climate remains inviting for those exploring the beauty of this charming coastal city. For a deeper dive into the weather patterns and climate of Otaru, check out Otaru Climate.