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

October reports an average high-temperature of a still moderately hot 84.6°F (29.2°C), slightly varied from September's 84.9°F (29.4°C). October nights document an average temperature reading of 79.2°F (26.2°C).

Heat index

October's average heat index is estimated at a very hot 95°F (35°C). Exercise increased caution, heat cramps and heat exhaustion are potential hazards. Continuous activity could lead to heatstroke.
In reference to the heat index, it's for places in shade and with a slight wind. Exposure to the direct sun could elevate the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', binds temperature metrics with humidity values to give a sense of the actual warmth. Additional elements encompassing metabolic differences, the degree of physical activity, and attire can impact the individual's perception of temperature. Direct sun exposure is noteworthy in its ability to escalate the felt temperature, potentially adding 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are highly critical to babies and toddlers. Kids are generally in more danger than adults because they perspire less. Their large skin surface area compared to their small bodies and the excessive heat due to their actions raises their risk.
Normally, the human body cools itself through perspiration, which removes excessive heat by evaporating sweat. When relative humidity is at high levels, the evaporation rate lessens, causing the body to keep more heat than it would in less humid conditions. If the body retains more heat than it can expel, the increasing temperature can lead to heat-related conditions.

Humidity

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, 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: Engaging in water activities, such as swimming or diving, in temperatures from 77°F (25°C) to 84.2°F (29°C) is very pleasurable for extended periods, without any discomfort.

Daylight

In October, the average length of the day 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

April through November, with an average maximum UV index of 7, are months with the highest UV index. A UV Index value of 6 to 7 symbolizes a high threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: The maximum UV index, 7 during October, leads to the following recommendations:
Inhibit overexposure. Warding off sun damage is of utmost importance. Avoid exposure to the Sun and try to stay in the shade between 10 a.m. and 4 p.m., when UV radiation is most potent, but be aware that parasols or canopies may not offer full protection. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly. Take caution! The UV rays from the Sun gain strength from sand and water reflections.