Guanica Monthly Rainfall & Precipitation
This page shows both the average monthly rainfall and the number of rainy days in Guanica, Puerto Rico. This average is based on long-term data collected between 1990 and 2020. Let's now guide you through the details for a complete overview.
Generally, Guanica receives mid-range precipitation levels, with 798 mm (31 in) annually. The distribution varies significantly throughout the year, with a distinct dry season during certain months, as shown in our charts below.
Monthly Precipitation Levels
The average number of days each month with precipitation (> 0.2 mm (0.01 in))
Significant seasonal changes in precipitation occur throughout the year. During the wettest month, September receives substantial rainfall, averaging 132 mm (5.2 in) of precipitation, recorded across 17 rainy days.
In contrast, the driest month, January brings less rainfall, with 22 mm (0.9 in) over 19 rainy days.
September, the wettest month, has a maximum daytime temperature of 30°C (86°F). During the driest month January you can expect a temperature of 29°C (84°F). For more detailed insights into the city's temperatures, visit our Guanica Temperature page.
Explore Guanica's Historical Precipitation: 1976-2026
Browse day-by-day precipitation records for Guanica spanning 51 years. Select any month and year to see actual rainfall and snowfall recorded on each day.
Annual Rainfall in Puerto Rico: City Comparison
The map below shows the annual precipitation across Puerto Rico. You can also select the different months in case you are interested in a specific month.
heavy rainfall
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moderate
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Guanica vs World: Rainfall Compared
Guanica's average annual precipitation is 798 mm (31 in). Let's compare this to some popular worldwide tourist destinations:
Seville, Spain, experiences 541 mm (21 in) of rainfall annually, with wet winters and dry summers typical of southern Spain.
Beijing, China, receives 560 mm (22 in) of annual precipitation, concentrated in the summer months.
In Tokyo, Japan, the average annual precipitation is 1528 mm (60 in), with significant summer rains due to typhoon season.
Mumbai, India, experiences a tropical monsoon climate with 1860 mm (73 in) of annual rainfall, with the majority of precipitation happening during the monsoon season from June to September.
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.
Climate change is affecting precipitation patterns worldwide, including Guanica:
- 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 Guanica's weather, including sunshine hours, humidity levels, and temperature data, visit our Guanica Climate page.
