Negombo Monthly Rainfall & Precipitation
This page shows both the average monthly rainfall and the number of rainy days in Negombo, Gampaha District, Sri Lanka. These values are calculated using 30 years of data (1990–2020) to ensure accuracy. Now, let's explore all the details to give you a full picture.
Negombo experiences significant rainfall throughout the year, averaging 2342 mm (92 in) of precipitation annually. However, this abundant rainfall is not evenly distributed, with a distinct rainy season during certain months. You can clearly see this in our monthly precipitation graphs below.
Monthly Precipitation Levels
The average number of days each month with precipitation (> 0.2 mm (0.01 in))
Negombo can be quite wet during October, receiving approximately 338 mm (13 in) of precipitation over 15 rainy days.
In contrast January, experiences much drier conditions, with 48 mm (1.9 in) of rainfall, spread across 4 rainy days.October, the wettest month, has a maximum daytime temperature of 30°C (86°F). The city receives 202 hours of sunshine in this period. During the driest month January you can expect a temperature of 31°C (88°F). For more detailed insights into the city's temperatures, visit our Negombo Temperature page.
Daily Historical Precipitation
44-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in May
Explore Negombo's Historical Precipitation: 1976-2026
Browse day-by-day precipitation records for Negombo spanning 51 years. Select any month and year to see actual rainfall and snowfall recorded on each day.
Annual Rainfall in Sri Lanka: City Comparison
The map below shows the annual precipitation across Sri Lanka. You can also select the different months in case you are interested in a specific month.
heavy rainfall
high
moderate
low
almost none
Negombo vs World: Rainfall Compared
Negombo's average annual precipitation is 2342 mm (92 in). Let's compare this to some popular worldwide tourist destinations:
In Toronto, Canada, annual precipitation averages 964 mm (38 in), with snowy winters and rainy summers.
In Shanghai, China, the annual average precipitation is 1347 mm (53 in), with a humid subtropical climate.
In Tokyo, Japan, the average annual precipitation is 1528 mm (60 in), with significant summer rains due to typhoon season.
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.
The proximity of a location to a large body of water can significantly affect its rainfall patterns:
- Ocean Influence: Coastal regions typically receive more rainfall due to the presence of moisture-laden winds from the ocean. These regions tend to have more humid climates and experience more frequent precipitation, especially in winter.
- Continental Climates: Areas further from the sea, such as inland or continental regions, experience less frequent rainfall and more extreme seasonal variations in precipitation.
- "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 Negombo's weather, including sunshine hours, humidity levels, and temperature data, visit our Negombo Climate page.
