September weather forecast
Arroyo, PR

September weather in Arroyo denotes a slight drop in air and sea temperatures. Yet it continues to register the highest rainfall volumes for the year at 4.29" (109mm), which may lead to sporadic interruptions in outdoor activities. As this month commences, the transition from the warm season to slightly cooler temperatures begins. Extended daylight hours persist, yielding abundant time to appreciate the city’s natural wealth and cultural vibrancy. Consistent winds characterize Arroyo's weather in September, making it an essential part of the city's climate portrait.

Temperature

Arroyo, Puerto Rico, in September witnesses an average high-temperature of a still moderately hot 85.1°F (29.5°C), indicating a slight variation from August's 85.3°F (29.6°C). The temperature during September sees a subtle transition from day to night, averaging a low of 76.3°F (24.6°C).

Heat index

September's mean heat index is calculated to be a torrid 96.8°F (36°C). Implement enhanced safety actions, heat cramps and heat exhaustion could occur. Sustained activity might result in heatstroke.
It is important to note that the heat index values are for shaded areas and light wind scenarios. Exposure to the direct sun might augment heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'felt air temperature', is a single figure representing how weather conditions feel when combining temperature and humidity. Additional factors encompassing metabolic differences, the level of physical activity, and clothing can impact the individual's perception of temperature. Direct sun rays have a notable impact on perceived temperature, which can raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly important for children. Kids are usually in more danger than grown-ups as they tend to sweat less. Plus, their bigger skin surface in relation to their small frames and increased heat generation due to their activity level make them more susceptible.
The human body cools itself through perspiration, as excessive warmth is removed from the body through sweat evaporation. With a lot of moisture in the air, the evaporation process is not as effective, and the body does not cool down as efficiently, creating a perception of overheating. When the body's heat gain surpasses its removal capacity, body temperature starts to climb, leading to potential heat-related ailments.

Humidity

In Arroyo, the average relative humidity in September is 80%.

Rainfall

The month with the most rainfall in Arroyo is September, when the rain falls for 23.7 days and typically aggregates up to 4.29" (109mm) of precipitation.

Ocean temperature

With an average ocean temperature of 85.5°F (29.7°C), September is the month with the warmest seawater.
Note: Surface water temperatures between 77°F (25°C) and 84.2°F (29°C) offer outstanding conditions for any water activity, providing extreme pleasure for extended periods.

Daylight

In September, the average length of the day is 12h and 14min.
On the first day of September in Arroyo, sunrise is at 6:10 am and sunset at 6:37 pm. On the last day of the month, sunrise is at 6:14 am and sunset at 6:13 pm AST.

Sunshine

The average sunshine in September is 9h.

UV index

The months with the highest UV index in Arroyo are May through October, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high health vulnerability from exposure to the Sun's UV rays for ordinary individuals.
Note: A maximum high daily UV index of 7 during September translates into the following directions:
Exercise precautions and adapt sun safety practices. Defence against skin and eye affliction is paramount. Remember that UV radiation from the Sun is strongest between 10 a.m. and 4 p.m. Make an effort to limit direct sun exposure during this time. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses. Be attentive! The UV exposure is heightened with reflections from sand and water.