September weather forecast
Luquillo, PR

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Weather in September

The weather in Luquillo in September sees noticeable changes, indicative of the gradual shift towards cooler temperatures. The weather continues to be predominantly warm but sees less rainfall than August, going down to 1.77" (45mm). Subtly, the average wind speed also witnesses a decrease to 9.3mph (15km/h), the lowest of the year. Simultaneously, daylight hours continue their downward trajectory. As Luquillo bids adieu to summer, a hint of autumn becomes apparent in the environment.

Temperature

Luquillo registers an average high-temperature of a still warm 84°F (28.9°C) at the commencement of September, closely related to the preceding month. The nights of September in Luquillo anticipate a slight dip from daytime high temperatures, settling to an average low-temperature of 80.8°F (27.1°C).

Heat index

During September, the heat index is estimated at a tropical 93.2°F (34°C). Take more preventive steps, risk of heat exhaustion and heat cramps is elevated. Long activity may culminate in heatstroke.
When assessing, remember that heat index measurements are for light winds and shaded spots. Direct sunlight might cause an increase of up to 15 Fahrenheit (8 Celsius) degrees in the heat index.
Note: The heat index, also known as 'apparent temperature' or 'feels like', is a value derived by merging air temperature with the humidity to convey how the climate feels. Additional factors encompassing metabolic differences, the level of physical activity, and clothing can impact the individual's perception of temperature. Exposure to direct sun rays can influence the heat you feel, pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values remain especially vital for babies and toddlers. Young ones often disregard the necessity to rest and hydrate. Thirst usually indicates advanced dehydration - hence, it is key to stay hydrated, particularly during ongoing physical activities.

Humidity

The average relative humidity in September is 78%.

Rainfall

In Luquillo, in September, it is raining for 19.6 days, with typically 1.77" (45mm) of accumulated precipitation. In Luquillo, during the entire year, the rain falls for 216 days and collects up to 21.5" (546mm) of precipitation.

Daylight

In Luquillo, the average length of the day in September is 12h and 14min.
On the first day of the month, sunrise is at 6:08 am and sunset at 6:36 pm. On the last day of September, sunrise is at 6:13 am and sunset at 6:11 pm AST.

Sunshine

The average sunshine in September is 9.1h.

UV index

January, March through December, with an average maximum UV index of 7, are months with the highest UV index in Luquillo. A UV Index reading of 6 to 7 represents a high threat to health from unsafe exposure to UV radiation for ordinary individuals.
Note: The daily high UV index of 7 in September translates into this advice:
Refrain from overexposure. Fair-skinned individuals could burn in under 20 minutes. Stay in the shade and limit direct sun exposure between 10 a.m. and 4 p.m., when UV radiation is at its strongest. Remember, however, that not all shade structures provide full sun protection. Arm yourself against UV rays' harm with protective apparel and UV-filtering shades.

Frequently asked questions

How hot is it in September?

During September, Luquillo experiences an average high-temperature of 84°F (28.9°C) and a low-temperature of 80.8°F (27.1°C). The average heat index (a.k.a. 'real feel', 'feels like'), which combines air temperature and relative humidity, in September is estimated at 93.2°F (34°C).

What is the average humidity in September?

In September, the average relative humidity is 78%.

How much does it rain in September?

In Luquillo, in September, during 19.6 rainfall days, 1.77" (45mm) of precipitation is typically accumulated.

What is the average length of the day in September?

The average day length in September is 12h and 14min.

When are sunrise and sunset in September?

On the first day of September, sunrise is at 6:08 am and sunset at 6:36 pm. On the last day of the month, sunrise is at 6:13 am and sunset at 6:11 pm AST.

How many hours of sunshine does Luquillo have in September?

The average sunshine duration in September is 9.1h.

What is the month with the highest UV index?

The months with the highest UV index are January, March through December, with an average maximum UV index of 7.

How high is the UV index in September?

In Luquillo, the average daily maximum UV index in September is 7. A UV Index of 6 to 7 symbolizes a high hazard to health from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Luquillo, PR

Average temperature in September - Luquillo, PR
  • Average high temperature in September: 84°F

The warmest month (with the highest average high temperature) is August (84.2°F).
The month with the lowest average high temperature is March (79°F).

  • Average low temperature in September: 80.8°F

The months with the highest average low temperature are September and October (80.8°F).
The coldest months (with the lowest average low temperature) are February and March (75.7°F).

Average pressure in September
Luquillo, PR

Average pressure in September - Luquillo, 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
Luquillo, PR

Average wind speed in September - Luquillo, PR
  • Average wind speed in September: 9.3mph

The windiest month (with the highest average wind speed) is July (12mph).
The calmest month (with the lowest average wind speed) is October (8.6mph).

Average humidity in September
Luquillo, PR

Average humidity in September - Luquillo, PR
  • Average humidity in September: 78%

The months with the highest relative humidity are May, June, July and August (79%).
The months with the lowest relative humidity are February and March (76%).

Average rainfall in September
Luquillo, PR

Average rainfall in September - Luquillo, PR
  • Average rainfall in September: 1.77"

The wettest month (with the highest rainfall) is August (2.83").
The driest month (with the least rainfall) is February (1.06").

Average rainfall days in September
Luquillo, PR

Average rainfall days in September - Luquillo, PR
  • Average rainfall days in September: 19.6 days

The month with the highest number of rainy days is August (21.3 days).
The month with the least rainy days is February (13.8 days).

Average daylight in September /
Average sunshine in September
Luquillo, PR

Average daylight in September / Average sunshine in September - Luquillo, PR
  • Average daylight in September: 12h and 1min

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 1min

The month with the most sunshine is June (Average sunshine: 10h and 36min).
The month with the least sunshine is December (Average sunshine: 6h and 24min).

Average sunshine days in September
Luquillo, PR

Average sunshine days in September - Luquillo, PR
  • Average sunshine days in September: 6.7 days

The month with the most sunshine days is March (10 days).
The month with the least sunshine days is November (4.9 days).

Average UV index in September
Luquillo, PR

Average UV index in September - Luquillo, PR
  • Average UV index in September: 7

The months with the highest UV index are January, March, April, May, June, July, August, September, October, November and December (UV index 7).
The month with the lowest UV index is February (UV index 6).

Average cloud cover in September
Luquillo, PR

Average cloud cover in September - Luquillo, PR
  • Average cloud cover in September: 33

The months with the most cloud cover are May and July (Cloud cover 40).
The months with the least cloud cover are February, September and October (Cloud cover 33).

Average visibility in September
Luquillo, PR

Average visibility in September - Luquillo, 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).

Luquillo, Puerto Rico, USA

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