Hachioji Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in Hachioji, Tokyo Prefecture, Japan. These averages rely on historical data collected over 30 years, from 1990 to 2020. Now, let's break down all the details for a clearer picture.

Hachioji is known for its substantial rain/snowfall, with annual precipitation reaching 1955 mm (77 in). While the overall climate is wet, there are notable seasonal patterns that create interesting contrasts, as demonstrated in our graph below.

Monthly Precipitation Levels

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

Hachioji can be quite wet during September, receiving approximately 255 mm (10 in) of precipitation over 19 rainy days.

In contrast December, experiences much drier conditions, with 73 mm (2.9 in) of rainfall, spread across 7 rainy days.

September, the wettest month, has a maximum daytime temperature of 26°C (79°F). The city receives 137 hours of sunshine in this period. During the driest month December you can expect a temperature of 11°C (52°F). For more detailed insights into the city's temperatures, visit our Hachioji Temperature page.

Hachioji's average annual precipitation is 1955 mm (77 in). Let's compare this to some popular worldwide tourist destinations:

The city of Rome, Italy, has an average annual precipitation of 832 mm (33 in), spread fairly evenly throughout the year.

Osaka, Japan, experiences 1507 mm (59 in) of rainfall annually, spread across the year with wetter summers.

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 Hachioji's weather, including sunshine hours, humidity levels, and temperature data, visit our Hachioji Climate page.