Hainan Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in Hainan, China. The figures are based on a 30-year period (1990–2020) to provide a reliable average. Let's now guide you through the details for a complete overview.

Generally, Hainan has a moderate amount of precipitation, averaging 507 mm (20 in) of rain/snowfall annually. However, it does experience a distinct dry season during certain months. Take a look at our detailed charts below to see the seasonal variation.

Monthly Precipitation Levels

The average number of days each month with precipitation (> 0.2 mm (0.01 in))

The climate in Hainan shows significant variation throughout the year. Expect 111 mm (4.4 in) of precipitation during the wettest month July, distributed over 16 rainy days.

In contrast, December offers drier and sunnier days, with around 3.8 mm (0.1 in) of snowfall over a single snowy day.

July, the wettest month, has a maximum daytime temperature of 21°C (70°F). During the driest month December you can expect a temperature of 1°C (34°F). For more detailed insights into the city's temperatures, visit our Hainan Temperature page.

Hainan's average annual precipitation is 507 mm (20 in). Let's compare this to some popular worldwide tourist destinations:

The climate in San Francisco, USA, is influenced by coastal weather, with 469 mm (18 in) of rainfall mostly during the winter months.

In Shanghai, China, the annual average precipitation is 1347 mm (53 in), with a humid subtropical climate.

In Brisbane, Australia, the annual precipitation is 979 mm (39 in), making it wetter than Sydney.

Ho Chi Minh City, Vietnam, receives 1955 mm (77 in) of annual rainfall, with a pronounced wet season from May to November, typical of its tropical monsoon climate.

Precipitation amounts are measured using specific gauges installed at weather stations, collecting both rain and snow and any other type of precipitation. Rainfall is measured directly in millimeters, while that from snow and ice is obtained by melting it. Automated systems often incorporate heaters to make this easier.

Information from these stations is transmitted via Wi-Fi, satellite, GPS, or telephone connections to central monitoring networks. This information is immediately updated and integrated into weather models and forecasts.

Precipitation has a very strong role in determining the local climate and ecosystem:

• Changing Rainfall Patterns: Global warming causes drastic changes in the patterns of rainfall. Some areas have been experiencing increased frequency and intensity of rainfall, while other areas experience longer dry spells or even droughts.
• Local Impacts: Many regions are experiencing heavier rainfall in the winter months and drier, hotter summers. This affects agriculture, water resources, and ecosystems.

• "Ginger" was the longest-lasting Atlantic tropical storm, which spun around the open ocean for 28 days in 1971.
• The world's largest snowflake was recorded in the Guinness Book of Records, at 38 cm (15 inches) wide and 20 cm (7.9 inches) thick. The snowflake fell at Fort Keogh, Montana, USA, on 28 January 1887.
• The greatest snowfall recorded was on Mt. Rainier, Washington State, USA, over 31.5 meters (103 feet) fell during the winter of 1972.

For more detailed information about Hainan's weather, including sunshine hours, humidity levels, and temperature data, visit our Hainan Climate page.