September weather forecast
Vega Alta, PR

In Vega Alta, September experiences a slight cooling down from the peak temperatures of August but remains notably hotter than the following October. This month witnesses the highest rainfall in inches signifying the onset of the wet season. With the decrease in daylight hours, the days start becoming shorter. Yet, the sunshine hours increase marginally, hinting at clearer skies. Wind conditions in September moderate further, with gusts measuring only 10.9mph (17.5km/h) on average.

Temperature

The onset of September brings with it an average high-temperature of a still moderately hot 85.1°F (29.5°C), showing a negligible variation from the month before. During September, Vega Alta's nights hold steady with an average temperature of 78.4°F (25.8°C), barely dropping from the daytime highs.

Heat index

During September, the heat index is appraised at a very hot 96.8°F (36°C). Incorporate additional preventive steps, heat exhaustion and heat cramps are possible. Long-lasting activity may cause heatstroke.
Heat index determinations are made taking into account the shade and light air movements. Exposing to direct sunshine may enhance heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. Depending on the activity and the individual's heat perception, which may vary due to factors including wind, clothing, and metabolic variations, this effect remains subjective. Always consider that direct sunlight exposure might heighten the heat's effects, pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. Young ones often do not realize the necessity to rest and replenish their fluids. Thirst is a delayed indication of dehydration - keeping hydrated, particularly in prolonged physical activity, is crucial.
The human body cools itself through perspiration, as excessive warmth is removed from the body through sweat evaporation. When the air holds a significant amount of moisture, the efficiency of the evaporation process is decreased, preventing the body from cooling down efficiently, leading to the sensation of overheating. With body temperatures on the rise, inefficient heat shedding can lead to dehydration and its associated complications.

Humidity

The average relative humidity in September is 78%.

Rainfall

In Vega Alta, in September, it is raining for 20.4 days, with typically 3.62" (92mm) of accumulated precipitation. Throughout the year, there are 223.5 rainfall days, and 27.95" (710mm) of precipitation is accumulated.

Daylight

In Vega Alta, Puerto Rico, the average length of the day in September is 12h and 14min.
On the first day of the month, sunrise is at 6:10 am and sunset at 6:39 pm. On the last day of September, sunrise is at 6:15 am and sunset at 6:14 pm AST.

Sunshine

In Vega Alta, the average sunshine in September is 9.4h.

UV index

The months with the highest UV index are May through November, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high health vulnerability from unsafe exposure to UV radiation for the average person.
Note: In September, a regular UV index of 7 translates into these guidelines:
Dodge overexposure. Fair-skinned people can get singed in less than 20 minutes. Seek shade and limit direct sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Keep in mind that shade structures like parasols or canopies do not offer complete sun protection. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense.