October weather forecast
San Juan, PR

October in San Juan observes a change in weather patterns as temperatures begin to cool modestly. Average high temperatures drop slightly to 84.6°F (29.2°C), well aligned with decreasing sea temperatures of 84.4°F (29.1°C). Rainfall records its highest values of the year at 1.5" (38mm) over 15.8 days. Coupled with decreased sunlight hours, cloud cover rises, setting a mellower tone for the city. This shift in the weather brings a softer, more clement touch to San Juan's tropical climate.

Temperature

San Juan's average high-temperature in October is a still warm 84.6°F (29.2°C), indicating a subtle variation from September. October notes an average low temperature of 79.2°F (26.2°C), subtly down from the daytime highs.

Heat index

In October, the average heat index is calculated to be a torrid 95°F (35°C). Heightened precautions are necessary, heat cramps and heat exhaustion are potential risks. Continuous activity could lead to heatstroke.
Be aware that heat index ratings are designed for shaded locations and minor breezes. The heat index might be elevated by 15 Fahrenheit (8 Celsius) degrees due to direct sun exposure.
Note: The heat index, also known as 'real feel' or 'apparent temperature', reflects the feeling of heat when considering both air temperature and humidity. One's perception of temperature is subjective, varying based on their activity and individual heat perception, influenced by factors like wind, clothing, and metabolic variations. Keep aware, the sun, when shining directly, can intensify the heat experience, pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular significance for children. Kids generally face higher risks than adults as they sweat less. Along with their large skin surface compared to their small bodies and higher heat production due to their activities, their vulnerability is increased.
As a reaction to high temperatures, the human body begins to perspire, using the evaporation of sweat to lower its temperature. In the presence of high relative humidity, the evaporation rate diminishes, resulting in the body retaining more warmth compared to dry conditions. Accumulating more heat than the body can dissipate leads to an uptick in body temperature, with potential heat stress consequences.

Humidity

In San Juan, the average relative humidity in October is 78%.

Rainfall

In San Juan, in October, during 15.8 rainfall days, 1.5" (38mm) of precipitation is typically accumulated. Throughout the year, in San Juan, there are 159.9 rainfall days, and 12.01" (305mm) of precipitation is accumulated.

Ocean temperature

In San Juan, in October, the average water temperature is 84.4°F (29.1°C).
Note: Water temperatures ranging between 77°F (25°C) and 84.2°F (29°C) are regarded as very warm, making swimming, diving, and similar water activities pleasurable for extended periods.

Daylight

In San Juan, Puerto Rico, the average length of the day in October is 11h and 43min.
On the first day of the month, sunrise is at 6:15 am and sunset at 6:12 pm. On the last day of October, sunrise is at 6:23 am and sunset at 5:52 pm AST.

Sunshine

The average sunshine in October is 8.2h.

UV index

The months with the highest UV index are April through November, with an average maximum UV index of 7. A UV Index of 6 to 7 symbolizes a high health vulnerability from exposure to the Sun's UV rays for the ordinary person.
Note: A maximum high daily UV index of 7 during October translates into the following directions:
Use protective steps and abide by sun safety guidelines. Safeguarding against skin and eye harm is necessary. Avoid direct Sun exposure and seek shade between 10 a.m. and 4 p.m., when UV radiation is at its peak, but keep in mind that not all shade structures provide complete protection. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun. Attention! The reflection of both water and sand can increase the intensity of UV rays.