, the first month of the autumn, in Cozumel
, is still a hot month, with average temperature ranging between max 31.9°C (89.4°F) and min 23.6°C (74.5°F).
In Cozumel, Mexico
, the average high-temperature is almost the same as in August
- a still tropical 31.9°C (89.4°F). In Cozumel, the average low-temperature is 23.6°C (74.5°F).
The average heat index in September is estimated at a blazing hot 47.1°C (116.8°F). Beware - heat cramps and heat exhaustion are very likely. Heatstroke is imminent with prolonged activity.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.Note
: The heat index, also known as 'felt air temperature', 'real feel', 'feels like', or 'apparent temperature', combines air temperature and relative humidity to represent a human perceived temperature equivalent. This effect is individual, with diverse people perceiving weather differently for numerous reasons (pregnancy, clothing, wind), and activity. Be aware that direct exposure to sunlight increases heat impact, and may raise the heat index additionally, by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
Perspiration is the human body's physiological response to high temperatures and is an attempt to lower body temperature through evaporation of sweat. 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 heat gain exceeds the level the body can remove, body temperature begins to rise, and heat-related illnesses and disorders may develop.
September is the most humid month, with an average relative humidity of 87%.
In Cozumel, during September, the rain falls for 15.4 days and regularly aggregates up to 240.2mm (9.46") of precipitation. In Cozumel, Mexico, during the entire year, the rain falls for 119.9 days and collects up to 1489.9mm (58.66") of precipitation.
, with an average sea temperature of 29°C (84.2°F), are months with the warmest seawater in Cozumel.Note
: For any water activity, surface water temperatures between 25°C (77°F) and 29°C (84.2°F) are considered as excellent and extremely pleasant for lengthened periods.
In Cozumel, Mexico, the average length of the day is 12.2h.
Months with the least sunshine are September and November
, with an average of 6.1h of sunshine.
The average daily maximum UV index in September is 11. A UV Index reading of 11, and higher, represents an ultimate health vulnerability from unprotected exposure to the Sun's UV rays for average individuals.Note
: In September, the average maximum UV index of 11 translate into the following recommendations:
Take all necessary precautions, as unprotected skin can burn in minutes. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Even on cloudy days, a sunscreen with a minimum 30 sun protection factor should be generously applied and frequently re-applied, including after every swim or outdoor exercise. Caution! The reflection of sand and water significantly increases the intensity of the Sun's UV radiation.