Climate - Haikou (Hainan)

Haikou's climate is subtropical, with very mild or pleasantly warm winters and hot, humid and rainy summers. The rains are abundant from May to October.
The city is the capital of the province of Hainan and is located in the far south of China, at 20 degrees north latitude, on the north coast of the island of Hainan.
Winter, from December to February, is very mild, however, the north-east monsoon brings cloudy days, during which there are some drizzles, or fog can form. Sometimes, cold and windy days can occur, with highs around 13 °C (55 °F) or even below. In January 2016, the temperature dropped to 6 °C (43 °F), with a maximum of 8 °C (46.5 °F).
Together with Southern China, Hainan can be hit by typhoons, the tropical cyclones of Southeast Asia. Typically, typhoons occur in this area from June to mid-November, but sometimes (though very rarely) they have affected this area outside of this period, i.e. in April or in May.

Best Time

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It is difficult to find the best time to visit Haikou, however you can choose the cooler period, from mid-November to the end of March. It must be said that we are on the north side of the island of Hainan, where there is not much sun in this period, and the sea is also cooler than on the southern side.

Haikou - Climate data

In Haikou, the average temperature of the coldest month (January) is of 18.4 °C (65.2 °F), that of the warmest month (June) is of 29.5 °C (85.2 °F). Here are the average temperatures.
In Haikou, precipitation amounts to 1625 millimeters (64 inches) per year: it is therefore abundant. It ranges from 20 mm (0.8 in) in the driest month (January) to 250 mm (9.8 in) in the wettest one (September). Here is the average precipitation.
At Haikou, the sea temperature ranges from 21 °C (70 °F) in January, February to 29 °C (84 °F) in June, July, August, September. Here are the average sea temperatures.
In Haikou, there are on average around 2070 sunshine hours per year. Here are the average hours of sunshine per day.

Haikou - Weather by month

Based on the period 1991-2020

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In January, the coldest month of the year, the weather in Haikou is usually warm. The average temperature is of 18.4 °C (65 °F), with a minimum of 15.6 °C (60.2 °F) and a maximum of 21.2 °C (70.1 °F).
On the coldest nights of the month, the temperature usually drops to around 10 °C (50 °F). However, it dropped to 5.9 °C (42.6 °F) in January 2016.
On the warmest days of the month, the temperature usually reaches around 28 °C (82 °F). However, it reached 32.1 °C (89.8 °F) in January 2006.
Precipitation amounts to 20 mm (0.8 in), distributed over 9 days.
The day lasts on average 11 hours and 5 minutes.
There are on average 3.5 hours of sunshine per day. So, the sun shines 32% of the time.
The average humidity is 84%. Hence, the air is normally humid.
The average wind speed is 10 kph (6 mph).
The average sea temperature is of 21 °C (70 °F). Therefore, the sea is cool for swimming.

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In February, the weather in Haikou is usually warm. The average temperature is of 19.8 °C (68 °F), with a minimum of 16.8 °C (62.3 °F) and a maximum of 22.7 °C (72.9 °F).
On the coldest nights of the month, the temperature usually drops to around 11 °C (51.5 °F). However, it dropped to 7 °C (44.6 °F) in February 2018.
On the warmest days of the month, the temperature usually reaches around 31 °C (87.5 °F). However, it reached 36.6 °C (97.9 °F) in February 1994.
Precipitation amounts to 35 mm (1.4 in), distributed over 11 days.
The day lasts on average 11 hours and 30 minutes.
There are on average 3.5 hours of sunshine per day. So, the sun shines 30% of the time.
The average humidity is 85%. Hence, the air is normally humid.
The average wind speed is 10 kph (6 mph).
The average sea temperature is of 21 °C (70 °F). Therefore, the sea is cool for swimming.

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In March, the weather in Haikou is usually warm to hot and muggy. The average temperature is of 23.0 °C (73 °F), with a minimum of 19.6 °C (67.3 °F) and a maximum of 26.4 °C (79.4 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 14 °C (57 °F). However, it dropped to 9.9 °C (49.8 °F) in March 2005.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 34.5 °C (94 °F). However, it reached 38.1 °C (100.6 °F) in March 1999.
Precipitation amounts to 50 mm (2 in), distributed over 10 days.
The day lasts on average 12 hours and 5 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 37% of the time.
The average humidity is 82%. Hence, the air is normally humid.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 22 °C (71.5 °F). Therefore, the sea is cool for swimming.

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In April, the weather in Haikou is usually warm to hot and muggy. The average temperature is of 26.3 °C (79 °F), with a minimum of 22.8 °C (73 °F) and a maximum of 29.9 °C (85.8 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 18 °C (64.5 °F). However, it dropped to 14.5 °C (58.1 °F) in April 1996.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 36.5 °C (97.5 °F). However, it reached 39.6 °C (103.3 °F) in April 2001.
Precipitation amounts to 105 mm (4.1 in), distributed over 12 days.
The day lasts on average 12 hours and 35 minutes.
There are on average 5.5 hours of sunshine per day. So, the sun shines 44% of the time.
The average humidity is 80%. Hence, the air is normally humid.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 24 °C (75 °F). Therefore, the sea is warm enough for swimming.

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In May, the weather in Haikou is usually very hot and muggy. The average temperature is of 28.5 °C (83 °F), with a minimum of 24.8 °C (76.6 °F) and a maximum of 32.1 °C (89.9 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 21.5 °C (71 °F). However, it dropped to 20 °C (68 °F) in May 2008.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 36.5 °C (98 °F). However, it reached 38.8 °C (101.8 °F) in May 2005.
Precipitation amounts to 185 mm (7.3 in), distributed over 16 days.
The day lasts on average 13 hours and 5 minutes.
There are on average 7 hours of sunshine per day. So, the sun shines 54% of the time.
The average humidity is 80%. Hence, the air is normally humid.
The average wind speed is 9 kph (6 mph).
The average sea temperature is of 27 °C (80.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In June, the hottest month of the year, the weather in Haikou is usually very hot and muggy. The average temperature is of 29.5 °C (85 °F), with a minimum of 25.7 °C (78.3 °F) and a maximum of 33.3 °C (92 °F).
On the coldest nights, the temperature usually drops to around 23.5 °C (74 °F). However, it dropped to 20.2 °C (68.4 °F) in June 2002.
On the warmest days, the temperature usually reaches around 36.5 °C (97.5 °F). However, it reached 37.7 °C (99.9 °F) in June 2003.
Precipitation amounts to 210 mm (8.3 in), distributed over 16 days.
The day lasts on average 13 hours and 20 minutes. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 7.5 hours of sunshine per day. So, the sun shines 56% of the time.
The average humidity is 79%. Hence, the air is normally humid.
The average wind speed is 9 kph (5 mph).
The average sea temperature is of 29 °C (84 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In July, the weather in Haikou is usually very hot and muggy. The average temperature is of 29.4 °C (85 °F), with a minimum of 25.8 °C (78.4 °F) and a maximum of 33.1 °C (91.6 °F).
On the coldest nights of the month, the temperature usually drops to around 23.5 °C (74.5 °F). However, it dropped to 22 °C (71.6 °F) in July 2004.
On the warmest days of the month, the temperature usually reaches around 36 °C (97 °F). However, it reached 37.7 °C (99.9 °F) in July 1998.
Precipitation amounts to 210 mm (8.3 in), distributed over 14 days.
The day lasts on average 13 hours and 10 minutes.
There are on average 8 hours of sunshine per day. So, the sun shines 62% of the time.
The average humidity is 79%. Hence, the air is normally humid.
The average wind speed is 9 kph (6 mph).
The average sea temperature is of 29 °C (84 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In August, the weather in Haikou is usually very hot and muggy. The average temperature is of 28.9 °C (84 °F), with a minimum of 25.6 °C (78 °F) and a maximum of 32.3 °C (90.1 °F).
On the coldest nights of the month, the temperature usually drops to around 23.5 °C (74.5 °F). However, it dropped to 22.3 °C (72.1 °F) in August 2014.
On the warmest days of the month, the temperature usually reaches around 35 °C (95 °F). However, it reached 37 °C (98.6 °F) in August 1994.
Precipitation amounts to 225 mm (8.9 in), distributed over 15 days.
The day lasts on average 12 hours and 50 minutes.
There are on average 7 hours of sunshine per day. So, the sun shines 55% of the time.
The average humidity is 81%. Hence, the air is normally humid.
The average wind speed is 8 kph (5 mph).
The average sea temperature is of 29 °C (84 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In September, the weather in Haikou is usually very hot and muggy. The average temperature is of 27.9 °C (82 °F), with a minimum of 24.9 °C (76.9 °F) and a maximum of 30.8 °C (87.5 °F).
On the coldest nights, the temperature usually drops to around 23 °C (73 °F). However, it dropped to 19.7 °C (67.5 °F) in September 1997.
On the warmest days, the temperature usually reaches around 33.5 °C (92.5 °F). However, it reached 35.7 °C (96.3 °F) in September 2006.
Precipitation amounts to 250 mm (9.8 in), distributed over 15 days.
The day lasts on average 12 hours and 10 minutes.
There are on average 6.5 hours of sunshine per day. So, the sun shines 53% of the time.
The average humidity is 81%. Hence, the air is normally humid.
The average wind speed is 9 kph (5 mph).
The average sea temperature is of 29 °C (84 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In October, the weather in Haikou is usually warm to hot and muggy. The average temperature is of 26.1 °C (79 °F), with a minimum of 23.4 °C (74.1 °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 °C (68.5 °F). However, it dropped to 15.5 °C (59.9 °F) in October 1991.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 32 °C (89.5 °F). However, it reached 34.5 °C (94.1 °F) in October 2003.
Precipitation amounts to 200 mm (7.9 in), distributed over 13 days.
The day lasts on average 11 hours and 40 minutes.
There are on average 5.5 hours of sunshine per day. So, the sun shines 49% 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 28 °C (82.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In November, the weather in Haikou is usually warm to hot and muggy. The average temperature is of 23.2 °C (74 °F), with a minimum of 20.6 °C (69.1 °F) and a maximum of 25.8 °C (78.5 °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 11.4 °C (52.5 °F) in November 2009.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 30 °C (86.5 °F). However, it reached 34.7 °C (94.5 °F) in November 1997.
Precipitation amounts to 95 mm (3.7 in), distributed over 10 days.
The day lasts on average 11 hours and 10 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 43% 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 25 °C (77 °F). Therefore, the sea is warm enough for swimming.

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In December, the weather in Haikou is usually warm. The average temperature is of 19.8 °C (68 °F), with a minimum of 17.3 °C (63.1 °F) and a maximum of 22.2 °C (72.1 °F).
On the coldest nights of the month, the temperature usually drops to around 11.5 °C (52.5 °F). However, it dropped to 7.4 °C (45.3 °F) in December 1991.
On the warmest days of the month, the temperature usually reaches around 27.5 °C (82 °F). However, it reached 31.2 °C (88.2 °F) in December 2012.
Precipitation amounts to 35 mm (1.4 in), distributed over 8 days.
The day lasts on average 10 hours and 55 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 4 hours of sunshine per day. So, the sun shines 39% of the time.
The average humidity is 79%. Hence, the air is normally humid.
The average wind speed is 10 kph (6 mph).
The average sea temperature is of 23 °C (73.5 °F). Therefore, the sea can be considered barely acceptable for swimming.