Climate - Ishigaki (Japan)

The climate of Ishigaki is sub-tropical, with very mild winters and long, moist and rainy summers.
Ishigaki is the most important of the Yaeyama Islands, an archipelago belonging to the southern Ryukyu islands, which is located to the east of Taiwan, and administratively is part of Okinawa prefecture. Other islands of the Yaeyama archipelago are Iriomote, Taketomijima, Kohamajima, Hatoma, Yubujima, Hateruma (the southernmost inhabited island of Japan), and Yonaguni (the westernmost one). The latitude of these islands is very low, just north of the Tropic of Cancer. Close to the islands is a coral reef.
Here are the average temperatures.

Although the winter is very mild, the sky is often cloudy, and periods of bad weather, with wind and rain, are quite common. Sometimes, especially in January, there may be very cool days, with highs around 16 °C (61 °F) or less and lows around 10 °C (50 °F).
The long summer is muggy, with fairly frequent and sometimes abundant rains. The first part of the rainy season, called the plum rains (Baiu), arrives in May and June, ie one month earlier than on the main islands of Japan, however, between one shower and another, the sun can come out, especially in June. In July, there is a relative pause, so that the rains decrease, and sunshine becomes pretty frequent.
Here are the average daily sunshine hours.

In the second part of summer (August, September, and early October), the rains increase again, but the amount of sunshine remains generally decent, at least until September. If all goes well, a week can pass without rain, otherwise, there may be periods of bad weather, or even typhoons.
In fact, from June to October, with a peak from August to early October, Ishigaki can be affected by typhoons, the tropical cyclones of Southeast Asia, which can bring strong winds and heavy rains.
Here is the average precipitation.



The sea in Ishigaki is never cold, in fact, the temperature drops to a minimum of 23 °C (73 °F) in February, so it's possible to try to swim even in winter, while it gets very warm in summer. Here are the average sea temperatures.

Ishigaki - Weather by month

Based on the period 1991-2020

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In January, the coldest month of the year, the weather in Ishigaki is usually warm. The average temperature is of 18.8 °C (66 °F), with a minimum of 16.3 °C (61.3 °F) and a maximum of 21.4 °C (70.5 °F).
On the coldest nights of the month, the temperature usually drops to around 12 °C (53.5 °F). However, it dropped to 8 °C (46.4 °F) in January 2016.
On the warmest days of the month, the temperature usually reaches around 25.5 °C (78.5 °F). However, it reached 27.3 °C (81.1 °F) in January 1995.
Precipitation amounts to 130 mm (5.1 in), distributed over 18 days.
The day lasts on average 10 hours and 50 minutes.
There are on average 2.5 hours of sunshine per day. So, the sun shines 25% of the time.
The average humidity is 72%. Hence, the air is normally humid.
The average wind speed is 18 kph (11 mph).
The average sea temperature is of 24 °C (75 °F). Therefore, the sea is warm enough for swimming.

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In February, the weather in Ishigaki is usually warm. The average temperature is of 19.3 °C (67 °F), with a minimum of 16.7 °C (62 °F) and a maximum of 21.9 °C (71.5 °F).
On the coldest nights of the month, the temperature usually drops to around 12.5 °C (55 °F). However, it dropped to 10 °C (50 °F) in February 1992.
On the warmest days of the month, the temperature usually reaches around 26.5 °C (79.5 °F). However, it reached 28 °C (82.4 °F) in February 2010.
Precipitation amounts to 140 mm (5.5 in), distributed over 17 days.
The day lasts on average 11 hours and 25 minutes.
There are on average 3.5 hours of sunshine per day. So, the sun shines 29% of the time.
The average humidity is 73%. Hence, the air is normally humid.
The average wind speed is 18 kph (11 mph).
The average sea temperature is of 23.5 °C (74 °F). Therefore, the sea can be considered barely acceptable for swimming.

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In March, the weather in Ishigaki is usually warm. The average temperature is of 20.9 °C (70 °F), with a minimum of 18.2 °C (64.7 °F) and a maximum of 23.6 °C (74.4 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 13.5 °C (56.5 °F). However, it dropped to 9.7 °C (49.5 °F) in March 2005.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 27.5 °C (81 °F). However, it reached 29 °C (84.2 °F) in March 2019.
Precipitation amounts to 130 mm (5.1 in), distributed over 17 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 4 hours of sunshine per day. So, the sun shines 32% of the time.
The average humidity is 74%. Hence, the air is normally humid.
The average wind speed is 17 kph (11 mph).
The average sea temperature is of 24 °C (75 °F). Therefore, the sea is warm enough for swimming.

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In April, the weather in Ishigaki is usually warm to hot and muggy. The average temperature is of 23.4 °C (74 °F), with a minimum of 20.8 °C (69.5 °F) and a maximum of 25.9 °C (78.7 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 16 °C (61 °F). However, it dropped to 13.4 °C (56.1 °F) in April 1996.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 29 °C (84.5 °F). However, it reached 31 °C (87.8 °F) in April 2019.
Precipitation amounts to 155 mm (6.1 in), distributed over 15 days.
The day lasts on average 12 hours and 50 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 34% of the time.
The average humidity is 77%. Hence, the air is normally humid.
The average wind speed is 16 kph (10 mph).
The average sea temperature is of 25 °C (77 °F). Therefore, the sea is warm enough for swimming.

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In May, the weather in Ishigaki is usually warm to hot and muggy. The average temperature is of 26.1 °C (79 °F), with a minimum of 23.6 °C (74.4 °F) and a maximum of 28.6 °C (83.4 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 20 °C (68 °F). However, it dropped to 17 °C (62.6 °F) in May 2013.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 31.5 °C (88.5 °F). However, it reached 33 °C (91.4 °F) in May 2018.
Precipitation amounts to 205 mm (8.1 in), distributed over 18 days.
The day lasts on average 13 hours and 20 minutes.
There are on average 5.5 hours of sunshine per day. So, the sun shines 40% of the time.
The average humidity is 79%. Hence, the air is normally humid.
The average wind speed is 15 kph (10 mph).
The average sea temperature is of 26.5 °C (80 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In June, the weather in Ishigaki is usually very hot and muggy. The average temperature is of 28.6 °C (83 °F), with a minimum of 26.3 °C (79.3 °F) and a maximum of 30.9 °C (87.6 °F).
On the coldest nights, the temperature usually drops to around 22.5 °C (72.5 °F). However, it dropped to 19.5 °C (67.1 °F) in June 2000.
On the warmest days, the temperature usually reaches around 33 °C (91.5 °F). However, it reached 34.6 °C (94.3 °F) in June 2007.
Precipitation amounts to 205 mm (8.1 in), distributed over 18 days.
The day lasts on average 13 hours and 35 minutes. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 7 hours of sunshine per day. So, the sun shines 52% of the time.
The average humidity is 81%. Hence, the air is normally humid.
The average wind speed is 18 kph (11 mph).
The average sea temperature is of 28 °C (83 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In July, the warmest month of the year, the weather in Ishigaki is usually very hot and muggy. The average temperature is of 29.8 °C (86 °F), with a minimum of 27.3 °C (81.2 °F) and a maximum of 32.2 °C (90 °F).
On the coldest nights of the month, the temperature usually drops to around 25 °C (77 °F). However, it dropped to 23.8 °C (74.8 °F) in July 2001.
On the warmest days of the month, the temperature usually reaches around 34 °C (93 °F). However, it reached 35.3 °C (95.5 °F) in July 2006.
Precipitation amounts to 130 mm (5.1 in), distributed over 16 days.
The day lasts on average 13 hours and 30 minutes.
There are on average 8.5 hours of sunshine per day. So, the sun shines 62% of the time.
The average humidity is 77%. Hence, the air is normally humid.
The average wind speed is 19 kph (12 mph).
The average sea temperature is of 29.5 °C (84.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In August, the weather in Ishigaki is usually very hot and muggy. The average temperature is of 29.4 °C (85 °F), with a minimum of 26.8 °C (80.2 °F) and a maximum of 32 °C (89.6 °F).
On the coldest nights of the month, the temperature usually drops to around 24.5 °C (76.5 °F). However, it dropped to 23 °C (73.4 °F) in August 2018.
On the warmest days of the month, the temperature usually reaches around 34 °C (93 °F). However, it reached 35.6 °C (96.1 °F) in August 2017.
Precipitation amounts to 260 mm (10.2 in), distributed over 18 days.
The day lasts on average 12 hours and 55 minutes.
There are on average 7.5 hours of sunshine per day. So, the sun shines 58% of the time.
The average humidity is 77%. Hence, the air is normally humid.
The average wind speed is 18 kph (11 mph).
The average sea temperature is of 29 °C (84.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In September, the weather in Ishigaki is usually very hot and muggy. The average temperature is of 28.2 °C (83 °F), with a minimum of 25.6 °C (78 °F) and a maximum of 31 °C (87.7 °F).
On the coldest nights, the temperature usually drops to around 23 °C (73.5 °F). However, it dropped to 20 °C (68 °F) in September 1997.
On the warmest days, the temperature usually reaches around 33 °C (91.5 °F). However, it reached 34.7 °C (94.5 °F) in September 2017.
Precipitation amounts to 260 mm (10.2 in), distributed over 17 days.
The day lasts on average 12 hours and 20 minutes.
There are on average 6.5 hours of sunshine per day. So, the sun shines 51% of the time.
The average humidity is 76%. Hence, the air is normally humid.
The average wind speed is 18 kph (11 mph).
The average sea temperature is of 28.5 °C (83.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In October, the weather in Ishigaki is usually warm to hot and muggy. The average temperature is of 26.1 °C (79 °F), with a minimum of 23.5 °C (74.3 °F) and a maximum of 28.8 °C (83.8 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 20.5 °C (69.5 °F). However, it dropped to 19 °C (66.2 °F) in October 1991.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 31.5 °C (88.5 °F). However, it reached 32.8 °C (91 °F) in October 2017.
Precipitation amounts to 204 mm (8 in), distributed over 16 days.
The day lasts on average 11 hours and 35 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 44% of the time.
The average humidity is 73%. Hence, the air is normally humid.
The average wind speed is 19 kph (12 mph).
The average sea temperature is of 27.5 °C (81.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In November, the weather in Ishigaki is usually warm to hot and muggy. The average temperature is of 23.6 °C (75 °F), with a minimum of 21.1 °C (70 °F) and a maximum of 26.1 °C (79.1 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 17.5 °C (63 °F). However, it dropped to 13 °C (55.4 °F) in November 2013.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 29 °C (84.5 °F). However, it reached 30.7 °C (87.3 °F) in November 2008.
Precipitation amounts to 155 mm (6.1 in), distributed over 17 days.
The day lasts on average 11 hours and 0 minutes.
There are on average 4 hours of sunshine per day. So, the sun shines 35% of the time.
The average humidity is 73%. Hence, the air is normally humid.
The average wind speed is 19 kph (12 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 December, the weather in Ishigaki is usually warm. The average temperature is of 20.4 °C (69 °F), with a minimum of 18 °C (64.4 °F) and a maximum of 22.9 °C (73.2 °F).
On the coldest nights of the month, the temperature usually drops to around 13.5 °C (56.5 °F). However, it dropped to 10 °C (50 °F) in December 2020.
On the warmest days of the month, the temperature usually reaches around 27 °C (81 °F). However, it reached 29.2 °C (84.6 °F) in December 1996.
Precipitation amounts to 125 mm (4.9 in), distributed over 18 days.
The day lasts on average 10 hours and 40 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 3 hours of sunshine per day. So, the sun shines 27% of the time.
The average humidity is 71%. Hence, the air is normally humid.
The average wind speed is 19 kph (12 mph).
The average sea temperature is of 25 °C (76.5 °F). Therefore, the sea is warm enough for swimming.