Cozumel
Mexico
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Cozumel, Mexico

A small blue boat, palm trees, and clear blue waters on Chen Rio white sandy beach in Cozumel, Mexico, with a small island
A small blue boat, palm trees, and clear blue waters on Chen Rio white sandy beach in Cozumel, Mexico, with a small island
September, the first month of the autumn, in Cozumel, is also a hot month, with temperature in the range of an average low of 23.6°C (74.5°F) and an average high of 31.9°C (89.4°F).

Temperature

In September, the average high-temperature is essentially 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).

Heat index

The average heat index is evaluated at a blazing hot 47.1°C (116.8°F). Be wary - heat exhaustion and heat cramps are highly anticipated. With continued activity, heatstroke is very likely.
Note that heat index values are valued for light wind and location in the shade. 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', 'apparent temperature', or 'feels like', is an index that combines air temperature and relative humidity to determine the human-perceived temperature equivalent. Additional factors like clothing, pregnancy, differences in body mass, height, and shape, and activity influence one's weather impression. 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 particularly important for children. 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.
To prevent overheating and help regulate its internal temperature, the human body sweat and rely on the evaporation to cool down. Under high air temperature and humidity (high heat index) conditions, perspiration is limited, and the perception of heat is increased. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.

Humidity

September is the most humid month, with an average relative humidity of 87%.

Rainfall

In Cozumel, Mexico, it is raining for 15.4 days, with typically 240.2mm (9.5") of accumulated precipitation. In Cozumel, during the entire year, the rain falls for 119.9 days and collects up to 1489.9mm (58.7") of precipitation.

Sea temperature

Months with the warmest seawater in Cozumel are July through October, with an average sea temperature of 29°C (84.2°F).
Note: For swimming, diving, and other water activities, temperatures between 25°C (77°F) and 29°C (84.2°F) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

Daylight

In Cozumel, the average length of the day in September is 12.2h.

Sunshine

September and November, with an average of 6.1h of sunshine, are months with the least sunshine.

UV index

In Cozumel, the average daily maximum UV index is 11. A UV Index estimate of 11, and higher, represents an ultimate health vulnerability from unsafe exposure to the UV radiation for the ordinary person.
Note: The average daily UV index of 11 in September transform into the following instructions:
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. Beware! The reflection of water and sand dramatically increases exposure to the UV rays.

What is the temperature in September in Cozumel?

In Cozumel, Mexico, in September, the average high-temperature is 31.9°C (89.4°F), and the average low-temperature is 23.6°C (74.5°F). The average heat index (a.k.a. 'real feel', 'apparent temperature'), that combines relative humidity and air temperature, in September is evaluated at 47.1°C (116.8°F).

What is the most humid month in Cozumel?

With an average relative humidity of 87%, September is the most humid month in Cozumel, Mexico.

What is the average humidity in September in Cozumel?

In Cozumel, Mexico, the average relative humidity in September is 87%.

How much does it rain in Cozumel in September?

In Cozumel, in September, it is raining for 15.4 days, with typically 240.2mm (9.5") of accumulated precipitation.

What are the months with the warmest sea water in Cozumel?

Months with the warmest seawater in Cozumel are July through October, with an average sea temperature of 29°C (84.2°F).

What is the water temperature in September in Cozumel?

In Cozumel, the average seawater temperature in September is 29°C (84.2°F). For swimming, diving, and other water activities, temperatures between 25°C (77°F) and 29°C (84.2°F) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

What is the average length of the day in September in Cozumel?

The average length of the day in September is 12.2h.

What is the month with the least sunshine in Cozumel?

September and November, with an average of 6.1h of sunshine, are months with the least sunshine.

How long on average sun shines in September in Cozumel?

The average sunshine in September in Cozumel, Mexico, is 6.1h.

How high is the UV index in September in Cozumel?

The average daily maximum UV index in September is 11. A UV Index of 11, and more, symbolizes an extreme health vulnerability from the exposure to the Sun's UV rays.
Average temperature in September - Cozumel, Mexico
  • Average high temperature in September: 31.9°C

The warmest month (with the highest average high temperature) is August (33°C).
Months with the lowest average high temperature are January and December (28.6°C).

  • Average low temperature in September: 23.6°C

The month with the highest average low temperature is June (23.8°C).
Coldest months (with the lowest average low temperature) are January and February (19.4°C).

Average humidity in September - Cozumel, Mexico
  • Average humidity in September: 87%

The month with the highest relative humidity is September (87%).
Months with the lowest relative humidity are March and April (79%).

Average rainfall in September - Cozumel, Mexico
  • Average rainfall in September: 240.2mm

The wettest month (with the highest rainfall) is October (242.5mm).
The driest month (with the lowest rainfall) is March (32.2mm).

Average rainfall days in September - Cozumel, Mexico
  • Average rainfall days in September: 15.4 days

The month with the highest number of rainy days is October (15.7 days).
The month with the lowest number of rainy days is April (3.7 days).

Average sea temperature in September - Cozumel, Mexico
  • Average sea temperature in September: 29°C

Best months for swimming (with the highest average sea temperature) are July, August, September and October (29°C).
Coldest months (with the lowest average sea temperature) are February and March (26°C).

Average daylight in September / Average sunshine in September - Cozumel, Mexico
  • Average daylight in September: 12.2h

The month with the longest days is June (Average daylight: 13.4h).
The month with shortest days is December (Average daylight: 10.9h).

  • Average sunshine in September: 6.1h

The month with most sunshine is April (Average sunshine: 8.6h).
Months with least sunshine are September and November (Average sunshine: 6.1).

Average UV index in September - Cozumel, Mexico
  • Average UV index in September: 11

Months with the highest UV index are April, May, June, July and August (UV index 12).
Months with the lowest UV index are January and December (UV index 7).