September weather forecastToa Alta, PR
September
Weather in September
September in Toa Alta signals the onset of the transition period from the hot to the cooler months. The temperature decline is gradual and moderate, bringing slight relief from the summer's peak heat. Changes in wind speed are also noticeable, indicating the upcoming shift in the season. The quantum of rainfall is high, accounting for a greener and fresher environment. The noteworthy climatic event of September is the considerable rainfall, recorded at a substantial 3.62" (92mm), indicating the wet season presence.Temperature
Toa Alta experiences an average high-temperature of a still moderately hot 85.1°F (29.5°C) with the onset of September, subtly varied from August's 85.5°F (29.7°C). During the nights of September, Toa Alta maintains an almost steady temperature with an average low of 78.4°F (25.8°C).Heat index
The average heat index in September is appraised at a torrid 96.8°F (36°C). Exercise increased caution, heat cramps and heat exhaustion are potential hazards. Continuous activity could lead to heatstroke.The standards for the heat index are set for locations in shade and under light breezes. Exposure to the direct sun could elevate the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'apparent temperature', is a composite of temperature and humidity figures to convey how warm it feels. A person's impression of weather can be affected by numerous aspects, among them metabolic variations, pregnancy, and activity levels. When in direct sunlight, one should be cautious as it can raise the heat index by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular significance for children. Children often overlook the necessity for resting and fluid replenishment. Thirst is a late sign of dehydration - thus, it is critical to stay hydrated, especially during extended periods of physical activities.
Evaporating sweat is a key way the human body dispels excessive warmth, all thanks to the process of perspiration. With an abundance of moisture present in the air, the process of evaporation becomes less effective, and the body fails to cool down as it should, leading to the sensation of overheating. Accumulating heat beyond the body's cooling measures leads to rising temperatures and potential ailments.
Humidity
The average relative humidity in September is 78%.Rainfall
In Toa Alta, Puerto Rico, 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 Toa Alta, 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 6:38 pm. On the last day of September, sunrise is at 6:15 am and sunset at 6:14 pm AST.
Sunshine
The average sunshine in September is 9.4h.UV index
May through November, with an average maximum UV index of 7, are months with the highest UV index. A UV Index of 6 to 7 symbolizes a high threat to health from unprotected exposure to Sun's UV rays for the average person.Note: An average UV index of 7 in September transforms into this advice:
Avoid excessive sunlight. Those with lighter skin may experience burning in less than 20 minutes. The Sun's UV radiation is at its strongest between the hours of 10 a.m. and 4 p.m. Minimize direct exposure to the sun during this period. Your best bet for sun defense on the face, eyes, and neck is a hat with a wide brim.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Toa Alta, PR
- Average high temperature in September: 85.1°F
The warmest month (with the highest average high temperature) is August (85.5°F).
The month with the lowest average high temperature is January (79.9°F).
- Average low temperature in September: 78.4°F
The months with the highest average low temperature are August, September and October (78.4°F).
The coldest month (with the lowest average low temperature) is March (73°F).
Average pressure in September
Toa Alta, PR
- Average pressure in September: 29.92"Hg
The months with the highest atmospheric pressure are January and February (30.02"Hg).
The month with the lowest atmospheric pressure is October (29.9"Hg).
Average wind speed in September
Toa Alta, PR
- Average wind speed in September: 7.6mph
The windiest month (with the highest average wind speed) is July (10mph).
The calmest month (with the lowest average wind speed) is October (6.8mph).
Average humidity in September
Toa Alta, PR
- Average humidity in September: 78%
The months with the highest relative humidity are May, June, July and November (79%).
The month with the lowest relative humidity is March (76%).
Average rainfall in September
Toa Alta, PR
- Average rainfall in September: 3.62"
The wettest month (with the highest rainfall) is October (3.82").
The driest month (with the least rainfall) is February (0.94").
Average rainfall days in September
Toa Alta, PR
- Average rainfall days in September: 20.4 days
The month with the highest number of rainy days is October (24 days).
The months with the least rainy days are January and February (14.2 days).
Average daylight in September /
Average sunshine in September
Toa Alta, PR
- Average daylight in September: 12h and 12min
The month with the longest days is June (Average daylight: 13h and 12min).
The month with the shortest days is December (Average daylight: 11h and 0min).
- Average sunshine in September: 9h and 24min
The months with the most sunshine are May and June (Average sunshine: 10h and 48min).
The month with the least sunshine is November (Average sunshine: 6h and 42min).
Average sunshine days in September
Toa Alta, PR
- Average sunshine days in September: 5.3 days
The month with the most sunshine days is January (9.8 days).
The months with the least sunshine days are October and November (3.5 days).
Average UV index in September
Toa Alta, PR
- Average UV index in September: 7
The months with the highest UV index are May, June, July, August, September, October and November (UV index 7).
The months with the lowest UV index are January, February, March, April and December (UV index 6).
Average cloud cover in September
Toa Alta, PR
- Average cloud cover in September: 26
The months with the most cloud cover are May, July and November (Cloud cover 34).
The month with the least cloud cover is September (Cloud cover 26).
Average visibility in September
Toa Alta, PR
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).





