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

September's transformation into October witnesses an average high-temperature of a still moderately hot 84.6°F (29.2°C), noting a minor change from the preceding month. The October nights show a slight decrease to a mean low-temperature of 79.2°F (26.2°C).

Heat index

During October, the heat index is calculated to be a torrid 95°F (35°C). Take extra safety measures to prevent heat exhaustion and heat cramps. Heatstroke could follow lengthy activity.
It is essential to grasp that the heat index's numbers are for shade and light wind settings. Being exposed to direct sunshine might trigger a heat index increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', is a measure that combines air temperature and relative humidity into a single value that indicates how hot the weather feels. The influence of weather can be personal, changing with an individual's body mass, height, and level of physical exertion. One's exposure to direct sunlight has the potential to intensify the heat sensation, increasing the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Juveniles are regularly less conscious of the need to recuperate and rehydrate. Thirst is a tardy symptom of dehydration - hydration, especially during lengthy physical activities, should be maintained.
Evaporating sweat, thanks to perspiration, acts as a natural air conditioner for the human body. In the presence of high relative humidity, the evaporation rate diminishes, resulting in the body retaining more warmth compared to dry conditions. When heat gain exceeds the level the body can remove, body temperature begins to rise, and heat-related illnesses and disorders may develop.

Humidity

The average relative humidity in October is 78%.

Rainfall

In San Juan, during October, the rain falls for 15.8 days and regularly aggregates up to 1.5" (38mm) of precipitation. In San Juan, during the entire year, the rain falls for 159.9 days and collects up to 12.01" (305mm) of precipitation.

Ocean temperature

In October, the average ocean temperature is 84.4°F (29.1°C).
Note: For swimming, diving, or other water activities, the temperature range of 77°F (25°C) to 84.2°F (29°C) is perceived as exceptionally enjoyable and comfortable even for prolonged periods.

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

In San Juan, 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 estimate of 6 to 7 represents a high threat to health from exposure to the Sun's UV rays for the ordinary person.
Note: The maximum UV index, 7 during October, leads to the following recommendations:
Deflect overexposure. Sun protection is a necessity. The Sun's UV radiation is most intense from 10 a.m. to 4 p.m. Try to avoid direct sun exposure during these hours. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses. Beware! Reflecting off water and sand, UV rays are much stronger.