September weather forecast
Cayo Largo, Cuba

The first month of the autumn, September, is still a hot month in Cayo Largo, Cuba, with an average temperature fluctuating between 23.5°C (74.3°F) and 31.6°C (88.9°F).

Temperature

In September, Cayo Largo's weather conditions record an average high-temperature of a still hot 31.6°C (88.9°F), demonstrating little divergence from the preceding month. Cayo Largo in September anticipates an average nighttime temperature of 23.5°C (74.3°F).

Heat index

For most parts of September, the heat index is evaluated at an extremely hot 43°C (109.4°F). Careful: Heat exhaustion and heat cramps are anticipated. With ongoing exertion, heatstroke becomes a possibility.
In terms of the heat index, values are set with light wind and shade conditions in mind. Direct sunlight can potentially boost the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', combines both the air temperature and the humidity level to give a perceived human temperature. The individual's temperature perception can be influenced by numerous factors such as metabolic variations, physical activity, and clothing. Direct sun rays can make one feel hotter, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it's vital to remain hydrated, particularly during prolonged physical activities.
Evaporation of sweat is the main factor behind the cooling effect of perspiration in the human body. Under conditions of high relative humidity, the rate of evaporation decreases. This results in the body retaining more heat than under conditions of dry air. Accumulating more heat than the body can dissipate leads to an uptick in body temperature, with potential heat stress consequences.

Humidity

The average relative humidity in September is 81%.

Rainfall

In September, in Cayo Largo, the rain falls for 19.1 days. Throughout September, 64mm (2.52") of precipitation is accumulated. Throughout the year, there are 143.3 rainfall days, and 542mm (21.34") of precipitation is accumulated.

Daylight

The average length of the day in September is 12h and 16min.
On the first day of September, sunrise is at 07:16 and sunset at 19:50. On the last day of the month, sunrise is at 07:25 and sunset at 19:22 CDT.

Sunshine

The average sunshine in September is 8.7h.

UV index

The months with the highest UV index are April through September, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high health risk from unsafe exposure to UV radiation for the average person.
Note: In September, the maximum UV index of 7 suggests this advice:
Stick with precautions and abide by sun safety procedures. Evading sunburn is essential. Stay out of direct sunlight and seek shade between 10 a.m. and 4 p.m., when UV radiation is strongest, but remember that shade devices may not offer full sun protection. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection.