São Luís Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in São Luís, Maranhão, Brazil. Long-term data from 1990 to 2020 was used to calculate these averages. Now, let's break down all the details for a clearer picture.

São Luís is known for its substantial rainfall, with annual precipitation reaching 2171 mm (85 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))

The seasons in São Luís, bring significant changes in precipitation. The wettest month, March, receives heavy rainfall, with an average of 434 mm (17 in) of precipitation. This rainfall is distributed across 31 rainy days.

In contrast, the driest month, September, experiences much less rainfall, totaling 18 mm (0.7 in) over 6 rainy days. These distinct seasonal differences provide diverse experiences throughout the year.

March, the wettest month, has a maximum daytime temperature of 29°C (84°F). The city receives 107 hours of sunshine in this period. During the driest month September you can expect a temperature of 31°C (88°F). For more detailed insights into the city's temperatures, visit our São Luís Temperature page.

Annual Rainfall in Brazil: City Comparison

The map below shows the annual precipitation across Brazil. You can also select the different months in case you are interested in a specific month.

São Luís vs World: Rainfall Compared

São Luís's average annual precipitation is 2171 mm (85 in). Let's compare this to some popular worldwide tourist destinations:

In Barcelona, Spain, the average annual precipitation is 644 mm (25 in), evenly distributed across the year with no extreme wet or dry seasons.

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

Melbourne, Australia, has 690 mm (27 in) of rainfall annually, spread fairly evenly throughout the year.

Kuala Lumpur, Malaysia, receives 2529 mm (100 in) of annual rainfall, characteristic of its equatorial tropical rainforest climate, with consistent rainfall throughout the year and peak months during March and November.

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.

• The U.S. has a significant number of thunderstorms every year, with over 14.6 million taking place across the world annually.
• Approximately 70% of lightning bolts strike land rather than oceans.
• A storm named John was the longest-lasting Pacific tropical storm, continuing for 31 days. As it crossed the dateline twice, it changed status from a hurricane to a typhoon and back to a hurricane.

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