Climate - Yokohama (Japan)

In Yokohama, the climate is temperate, with fairly mild, sunny winters and hot, humid and rainy summers. Like the rest of Japan, the city is affected by the monsoon circulation: in winter, the northwest cold currents will prevail, while in summer, they will be replaced by hot and humid currents of tropical origin.
Yokohama overlooks the sea in Tokyo Bay, not far from the Japanese capital. Given the relatively low latitude (we are on the 35th parallel), and the protection of the mountains (we are on the east side), in winter, the currents of Siberian origin are felt little, so there is a good number of sunny days, and it's usually not too cold. However, cold and windy periods, with highs around 5/7 °C (41/45 °F) or less and possible snowfalls, can not be ruled out.
In the postwar period, Yokohama's coldest record is -6 °C (21 °F), set in January 1963.
In any case, night frosts are rare and usually light.
In summer, hot and muggy periods, with highs around 35 °C (95 °F) and high humidity, alternate with periods of bad weather, with wind and rain, and sometimes (especially in June and July) temperatures a bit cool at night. August is the hottest month, both because of the thermal inertia of the sea and because of the lower frequency of periods of bad weather.
Here are the average temperatures.

Rainfall is abundant, in fact, it amounts to 1,700 millimeters (67 inches) per year. Winter is undoubtedly the driest season; the rainiest months are September and October, also because of the contribution given by typhoons. In August, there is a certain decrease in rain frequency: on average, among the summer months, it is the driest and sunniest as well as the hottest. Here is the average precipitation.

The cherry blossoming (Sakura) in Yokohama takes place around March 30: there are dedicated events in the streets and parks where you can admire them.
The amount of sunshine in Yokohama is good in winter (there are no less than 6 hours of sunshine per day in December and January), while it is just mediocre or decent in the other seasons because of the weather disturbances that pass in spring and autumn, as well as of the summer monsoon. However, among those of summer, August is the sunniest month. Here are the average sunshine hours per day.



The sea is warm enough for swimming, with a temperature of 23 °C (73 °F) or more, from July to October, as you can see in the following table.

As mentioned, from June to October (but especially from August to early October), Yokohama can be affected by typhoons, the tropical cyclones of South-East Asia, which mostly affect the southern part of the country but can also arrive here. The most intense typhoons can bring strong winds, torrential rains and heavy damage.

Yokohama - Weather by month

Based on the period 1991-2020

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In January, the coldest month of the year, the weather in Yokohama is usually quite cold. The average temperature is of 6.4 °C (44 °F), with a minimum of 2.7 °C (36.9 °F) and a maximum of 10.2 °C (50.4 °F).
On the coldest nights of the month, the temperature usually drops to around -0.5 °C (31 °F). However, it dropped to -2.7 °C (27.1 °F) in January 2018.
On the warmest days of the month, the temperature usually reaches around 16 °C (61 °F). However, it reached 19.7 °C (67.5 °F) in January 1996.
Precipitation amounts to 65 mm (2.6 in), distributed over 6 days.
The day lasts on average 10 hours and 5 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 62% of the time.
The average humidity is 53%.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 16.5 °C (62 °F). Therefore, the sea is cold for swimming.

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In February, the weather in Yokohama is usually quite mild. The average temperature is of 7.0 °C (45 °F), with a minimum of 3.1 °C (37.6 °F) and a maximum of 10.8 °C (51.4 °F).
On the coldest nights of the month, the temperature usually drops to around -0.5 °C (31.5 °F). However, it dropped to -2.8 °C (27 °F) in February 1996.
On the warmest days of the month, the temperature usually reaches around 18.5 °C (65.5 °F). However, it reached 24.8 °C (76.6 °F) in February 2009.
Precipitation amounts to 65 mm (2.6 in), distributed over 6 days.
The day lasts on average 10 hours and 55 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 55% of the time.
The average humidity is 54%.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 15.5 °C (60.5 °F). Therefore, the sea is cold for swimming.

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In March, the weather in Yokohama is usually mild. The average temperature is of 10 °C (50 °F), with a minimum of 6 °C (42.8 °F) and a maximum of 14 °C (57.2 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 1.5 °C (35 °F). However, it dropped to 0 °C (32 °F) in March 2003.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 21.5 °C (70.5 °F). However, it reached 24.5 °C (76.1 °F) in March 2013.
Precipitation amounts to 140 mm (5.5 in), distributed over 11 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 5.5 hours of sunshine per day. So, the sun shines 45% of the time.
The average humidity is 60%.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 16 °C (60.5 °F). Therefore, the sea is cold for swimming.

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In April, the weather in Yokohama is usually very mild. The average temperature is of 14.8 °C (59 °F), with a minimum of 10.7 °C (51.3 °F) and a maximum of 18.9 °C (66 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 4.5 °C (40.5 °F). However, it dropped to 0.8 °C (33.4 °F) in April 2001.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 25 °C (77 °F). However, it reached 28.4 °C (83.1 °F) in April 2005.
Precipitation amounts to 145 mm (5.7 in), distributed over 11 days.
The day lasts on average 13 hours and 5 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 46% of the time.
The average humidity is 65%.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 17.5 °C (63 °F). Therefore, the sea is cold for swimming.

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In May, the weather in Yokohama is usually warm. The average temperature is of 19.3 °C (67 °F), with a minimum of 15.5 °C (59.9 °F) and a maximum of 23.1 °C (73.6 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 10.5 °C (51.5 °F). However, it dropped to 7.9 °C (46.2 °F) in May 1993.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 28.5 °C (83.5 °F). However, it reached 31.3 °C (88.3 °F) in May 2019.
Precipitation amounts to 155 mm (6.1 in), distributed over 11 days.
The day lasts on average 14 hours and 5 minutes. So the days are long.
There are on average 6 hours of sunshine per day. So, the sun shines 43% of the time.
The average humidity is 70%.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 20 °C (68 °F). Therefore, the sea is very cool for swimming.

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In June, the weather in Yokohama is usually warm. The average temperature is of 22.3 °C (72 °F), with a minimum of 19.1 °C (66.4 °F) and a maximum of 25.5 °C (77.9 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 15 °C (59 °F). However, it dropped to 12.4 °C (54.3 °F) in June 2011.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 31 °C (88 °F). However, it reached 35.5 °C (95.9 °F) in June 2005.
Precipitation amounts to 190 mm (7.5 in), distributed over 14 days.
The day lasts on average 14 hours and 30 minutes. So the days are long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 4.5 hours of sunshine per day. So, the sun shines 31% of the time.
The average humidity is 78%. Hence, the air is normally humid.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 22 °C (72 °F). Therefore, the sea is cool for swimming.

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In July, the weather in Yokohama is usually warm to hot and muggy. The average temperature is of 26.2 °C (79 °F), with a minimum of 22.9 °C (73.2 °F) and a maximum of 29.4 °C (84.9 °F).
On the coldest nights of the month, the temperature usually drops to around 19 °C (66 °F). However, it dropped to 16.5 °C (61.7 °F) in July 1993.
On the warmest days of the month, the temperature usually reaches around 34.5 °C (94 °F). However, it reached 37.2 °C (99 °F) in July 2018.
Precipitation amounts to 185 mm (7.3 in), distributed over 12 days.
The day lasts on average 14 hours and 20 minutes. So the days are long.
There are on average 5.5 hours of sunshine per day. So, the sun shines 38% of the time.
The average humidity is 78%. Hence, the air is normally humid.
The average wind speed is 10 kph (6 mph).
The average sea temperature is of 24.5 °C (76 °F). Therefore, the sea is warm enough for swimming.

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In August, the warmest month of the year, the weather in Yokohama is usually very hot and muggy. The average temperature is of 27.6 °C (82 °F), with a minimum of 24.3 °C (75.7 °F) and a maximum of 31 °C (87.8 °F).
On the coldest nights of the month, the temperature usually drops to around 20 °C (68.5 °F). However, it dropped to 17.6 °C (63.7 °F) in August 1996.
On the warmest days of the month, the temperature usually reaches around 35 °C (95 °F). However, it reached 37.4 °C (99.3 °F) in August 2016.
Precipitation amounts to 140 mm (5.5 in), distributed over 9 days.
The day lasts on average 13 hours and 25 minutes.
There are on average 6.5 hours of sunshine per day. So, the sun shines 50% of the time.
The average humidity is 76%. Hence, the air is normally humid.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 26.5 °C (79.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In September, the weather in Yokohama is usually warm to hot and muggy. The average temperature is of 24.2 °C (75 °F), with a minimum of 21 °C (69.8 °F) and a maximum of 27.3 °C (81.1 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 16 °C (61 °F). However, it dropped to 12.2 °C (54 °F) in September 2001.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 32.5 °C (91 °F). However, it reached 35.6 °C (96.1 °F) in September 2010.
Precipitation amounts to 240 mm (9.4 in), distributed over 13 days.
The day lasts on average 12 hours and 25 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 38% of the time.
The average humidity is 76%. Hence, the air is normally humid.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 25.5 °C (77.5 °F). Therefore, the sea is warm enough for swimming.

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In October, the weather in Yokohama is usually warm. The average temperature is of 18.8 °C (66 °F), with a minimum of 15.7 °C (60.3 °F) and a maximum of 22 °C (71.6 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 11 °C (51.5 °F). However, it dropped to 7.7 °C (45.9 °F) in October 1993.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 28.5 °C (83 °F). However, it reached 32.4 °C (90.3 °F) in October 2018.
Precipitation amounts to 240 mm (9.4 in), distributed over 12 days.
The day lasts on average 11 hours and 20 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 39% of the time.
The average humidity is 71%. Hence, the air is normally humid.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 23 °C (73 °F). Therefore, the sea can be considered barely acceptable for swimming.

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In November, the weather in Yokohama is usually mild. The average temperature is of 13.6 °C (56 °F), with a minimum of 10.1 °C (50.2 °F) and a maximum of 17.1 °C (62.8 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 5.5 °C (41.5 °F). However, it dropped to 1.7 °C (35.1 °F) in November 2016.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 22.5 °C (73 °F). However, it reached 25.3 °C (77.5 °F) in November 2009.
Precipitation amounts to 110 mm (4.3 in), distributed over 9 days.
The day lasts on average 10 hours and 20 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 49% of the time.
The average humidity is 65%.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 21 °C (69.5 °F). Therefore, the sea is cool for swimming.

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In December, the weather in Yokohama is usually mild. The average temperature is of 8.8 °C (48 °F), with a minimum of 5.2 °C (41.4 °F) and a maximum of 12.5 °C (54.5 °F).
On the coldest nights of the month, the temperature usually drops to around 1.5 °C (34.5 °F). However, it dropped to -1.1 °C (30 °F) in December 1995.
On the warmest days of the month, the temperature usually reaches around 19 °C (66.5 °F). However, it reached 23.7 °C (74.7 °F) in December 2015.
Precipitation amounts to 65 mm (2.6 in), distributed over 6 days.
The day lasts on average 9 hours and 50 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 5.5 hours of sunshine per day. So, the sun shines 58% of the time.
The average humidity is 57%.
The average wind speed is 10 kph (6 mph).
The average sea temperature is of 18.5 °C (65.5 °F). Therefore, the sea is very cool for swimming.