Last updated: August 31, 2025
In San Isidro, Puerto Rico, the average temperature in December hovers around 26°C (78°F), offering a warm and inviting atmosphere. Daily temperatures can range from a minimum of 23°C (73°F) to a comfortable maximum of 31°C (87°F). Expect an average precipitation of 51 mm (2.0 in) over approximately 16 days, contributing to a 76% humidity level that enhances the tropical feel of the region.
In December in San Isidro, the average temperature is 26°C (78°F), with maximums reaching 31°C (87°F) and minimums dropping to as low as 23°C (73°F). This pleasant climate makes it an ideal time for travelers to explore and enjoy outdoor activities.
In San Isidro in December, the precipitation amount is 51 mm (2.0 in) distributed over 16 days.
In San Isidro in December humidity is 76%. With an average temperature of 26°C (78°F), this humidity feels like a warm, tropical embrace, making travel feel like a stroll through a steamy rainforest, where the air clings to your skin and every step can leave you drenched, yet there's a certain charm in the lush scenery and vibrant life all around.
In San Isidro in December, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in San Isidro.
UV Risk Categories
Weather in San Isidro varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in San Isidro, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 25°C (77°F) | 38 mm (1.5 inches) | 76% | very high |
| February Weather | 25°C (77°F) | 43 mm (1.7 inches) | 75% | extreme |
| March Weather | 25°C (77°F) | 67 mm (2.6 inches) | 74% | extreme |
| April Weather | 26°C (78°F) | 56 mm (2.2 inches) | 75% | extreme |
| May Weather | 27°C (80°F) | 64 mm (2.5 inches) | 75% | extreme |
| June Weather | 27°C (81°F) | 68 mm (2.7 inches) | 77% | extreme |
| July Weather | 28°C (82°F) | 87 mm (3.4 inches) | 80% | extreme |
| August Weather | 28°C (82°F) | 99 mm (3.9 inches) | 80% | extreme |
| September Weather | 28°C (82°F) | 173 mm (6.8 inches) | 79% | extreme |
| October Weather | 27°C (81°F) | 145 mm (5.7 inches) | 78% | extreme |
| November Weather | 26°C (80°F) | 106 mm (4.2 inches) | 78% | very high |
| December Weather | 26°C (78°F) | 51 mm (2.0 inches) | 76% | very high |