The week of 25 August 2025 - 31 August 2025 had an average daily temperature of 23 °C (73 °F) and a minimum (nighttime) temperature of 19 °C (66 °F). Both the daily and night temperatures in Otaru are roughly same as the long-term average, which is around 24 °C (75 °F) and 16 °C (61 °F) respectively. The beginning of the week saw Tuesday being the hottest day of the week. The average temperatures observed during different times of day (based on local time) were as below: 7am 21 °C (70 °F), 10am 22 °C (72 °F), 1pm 22 °C (72 °F), 4pm 22 °C (72 °F), 7pm 20 °C (68 °F), 10pm 20 °C (68 °F).

There were 1 day without rain, 3 days with light rain, 2 days with moderate rain and 1 day with heavy rain during this week. During the whole week, total of 122 mm (4.80 in) of precipitation was observed, which is above the long term average for Otaru, which is 31 mm (1.22 in). From dawn to dusk, there was an average of 88 % cloud coverage during the day.

An average wind speed of 2.4 m/s was recorded. The air pressure varied between 1000 hpa and 1016 hpa. The air in Otaru had an average humidity of 83 %.

On average, there were 1.5 hours partially overcast skies, 9 hours overcast skies and 3.5 hours rainy weather during the daytime (from dawn to dusk). Average time of sunrise was 04:55, average time of sunset was 18:19.

Weather overview

Otaru, Japan typically experiences a moderate continental climate with day temperatures varying widely throughout the year. In the colder month of January, temperatures can drop as low as -1 °C (30 °F) during the day and -7 °C (19 °F) at night. The warmest month, August, sees daytime temperatures reaching 25 °C (76 °F) and nighttime temperatures of 17 °C (63 °F). The driest month, June, witnesses only 10 days of precipitation, while January is the wettest, featuring rain on 24 days of the month.

January weather

In January, the daytime temperature hits its lowest point in Otaru at -1 °C (30 °F), while the nighttime temperature also records its lowest at -7 °C (19 °F). The onset of the wet season is evident with 139 mm (5.46 in) of rainfall and 24 days of precipitation at its peak.

February weather

Otaru witnesses the beginning of a rise in day temperatures in February. The wet season persists, though rainfall amounts continue to decrease, reaching 103 mm (4.06 in). The month also marks the start of a decline in the number of rainy days and an increase in sunshine hours to 3 hours.

March weather

A decrease in rainy days continues in Otaru with only 17 days, and a reduction in rainfall to 78 mm (3.08 in) is also apparent. Daytime temperatures continue their upward trend at 3 °C (38 °F); night temperatures begin to increase as well. Sunshine hours see an increase to 5 hours.

April weather

Day temperatures in Otaru in April show a similar increase to previous months, reaching 10 °C (50 °F), while the nighttime temperature also rises to 2 °C (35 °F). The continuation of the decline in rainy days to 11 days and a concurrent drop in rainfall amount to 61 mm (2.40 in) is observed. Humidity levels hit a year-long low at 68 %.

May weather

The upward trend of day temperatures in Otaru persists, with May seeing continued rises. The decline in rainy days seems consistent, registering 10 days. Sunlight hours peak at 6 hours.

June weather

With the tourist season's onset in June, Otaru experiences similar increases in daytime temperatures at 19 °C (66 °F), with a noticeable rise in night temperatures to 11 °C (51 °F). The number of rainy days reaches its yearly minimum at 10 days, and a low in rainfall is observed.

July weather

The tourist season peaks in July with daytime temperatures climbing to 23 °C (73 °F) and nighttime temperatures reaching 15 °C (60 °F). Rainfall starts to increase to 103 mm (4.05 in). Wind speeds drop to their lowest point at 4.

August weather

Observing the tourist season in full swing in August, there is a peak in both day and night temperatures in Otaru. Rainfall amounts show an upward trend similar to the previous month, measured at 133 mm (5.24 in), along with a beginning increase in the number of rainy days.

September weather

The tourist season persists in September, and Otaru witnesses a beginning decline in both day and nighttime temperatures. The number of rainy days continues to increase to 13 days, and sunshine hours start to rise again, reaching 6 hours.

October weather

There is a noticeable decline in daytime and nighttime temperatures in Otaru during October. The number of rainy days sees a rise to 16 days, and there's a start to the descent in rainfall amount at 119 mm (4.70 in). The decline in sunshine hours also becomes evident, with a reading of 5 hours.

November weather

The onset of the wet season is apparent in November, with a continued decrease in day temperatures at 8 °C (46 °F) and further cooling at night at 1 °C (33 °F). The rise in the number of rainy days continues with 20 days, and an increase in rainfall amount is observed at 145 mm (5.72 in).

December weather

The wet season is clearly in effect in December, with daytime temperatures descending to a similar extent as in the previous month at 1 °C (34 °F), and nighttime temperatures following suit to -5 °C (24 °F). Maximum rainfall is reached at 150 mm (5.91 in). The least amount of sunlight is seen during this month.

How cold can it get during the day and at night in Otaru in January?

In January, daytime temperatures in Otaru can plunge to -1 °C (30 °F), while nighttime conditions are even chillier at -7 °C (19 °F).

Does February in Otaru see an improvement in weather conditions?

February marks a gradual improvement in weather with decreasing rainfall and an uptick in sunshine, despite the continuation of the wet season.

What changes in weather pattern does March bring to Otaru?

March sees fewer rainy days, lowered rainfall, and the promise of milder days with slightly warmer temperatures.

Is April characterized by low humidity levels in Otaru?

Yes, April features the lowest humidity levels of the year in Otaru at 68 %.

In May, do the conditions in Otaru become more conducive to outdoor activities?

Certainly, May offers more sunshine hours and fewer rainy days, making it favorable for enjoying the outdoors.

How do temperature conditions fare during the beginning of the tourist season in Otaru in June?

The start of the tourist season in June sees comfortable daytime temperatures and the least number of rainy days, perfect for vacation-goers.

What is the trend for wind speeds in Otaru during the peak of the tourist season?

July experiences the calmest winds of the year, alongside the continued rise in temperatures and the onset of increased rainfall.

Does August maintain comfortable weather for visitors in Otaru despite increased rainfall?

While August brings higher rainfall, the temperatures remain comfortably warm for visitors.

As the tourist season continues, does September provide enough sunshine for activities in Otaru?

Yes, September still offers a decent amount of sunshine hours suitable for outdoor activities, despite the increasing rainy days.

Is the autumnal decrease in temperatures and sunshine hours significant in Otaru in October?

October marks a clear transition towards cooler weather with fewer sunshine hours, signifying the advance of autumn.

Does the shift to the wet season in November bring a significant increase in rainfall in Otaru?

Indeed, as the wet season commences, November brings a heightened chance of rainfall coupled with cooler temperatures.

In December, how does the minimal sunlight affect the daily activities in Otaru?

The limited sunlight in December results in shorter days and potentially impacts daily activities and plans.