September weather forecastCozumel, Mexico

Weather in September

In September, the weather in Cozumel begins a gradual transition towards the cooler months. A slight dip in daylight hours is compensated by increased sunshine, providing abundant hours for outdoor pursuits. The UV index drops to 11, but sun protection remains a must. Torrential showers grace the city in September, where the monthly rainfall achieves a maximum of 240mm (9.45").

Temperature

Cozumel, Mexico, notes an average high-temperature of a still hot 31.9°C (89.4°F) in September, displaying minor variation from August. Throughout September, Cozumel's nights cool down to an average of 23.6°C (74.5°F).

Heat index

September's heat index is computed to be a life-threatening hot 47°C (116.6°F). Stay vigilant: Heat cramps along with heat exhaustion are expected. Heatstroke may follow prolonged exertion.
Records show heat index calculations are tailored for shaded regions and mild winds. The heat index has the possibility to be enhanced by 15 Fahrenheit (8 Celsius) degrees when there is direct sun exposure.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', evaluates the perceived heat by adding the effect of moisture in the air. Factors such as metabolic variation, pregnancy, and physical activity play a role in one's impression of weather. You should know that direct sun exposure can heighten weather effects, potentially elevating the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly relevant to children. Young individuals usually face greater risks than adults as their sweat production is less. Also, their larger skin surface relative to their small bodies and the high heat generation due to their activity contributes to their vulnerability.
Perspiration is the human body's physiological response to high temperatures and is an attempt to lower body temperature through evaporation of sweat. In the presence of high relative humidity, the evaporation rate diminishes, resulting in the body retaining more warmth compared to dry conditions. If heat absorption isn't effectively countered by the body's cooling methods, body temperature surges, hinting at potential problems.

Humidity

The most humid month in Cozumel is September, with an average relative humidity of 87%.

Rainfall

In Cozumel, in September, during 15.4 rainfall days, 240mm (9.45") of precipitation is typically accumulated. Throughout the year, there are 119.9 rainfall days, and 1490mm (58.66") of precipitation is accumulated.

Sea temperature

July through October, with an average sea temperature of 29°C (84.2°F), are months with the warmest seawater.
Note: Water activities in surface temperatures between 25°C (77°F) and 29°C (84.2°F) are seen as exceptional and extremely agreeable for lengthened time spans.

Daylight

In Cozumel, the average length of the day in September is 12h and 15min.
On the first day of September, sunrise is at 6:31 am and sunset at 7:02 pm. On the last day of the month, sunrise is at 6:38 am and sunset at 6:36 pm EST.

Sunshine

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

UV index

In September, the average daily maximum UV index is 11. A UV Index value of 11, and more, symbolizes an ultimate health vulnerability from exposure to the Sun's UV radiation for the ordinary person.
Note: The UV index of 11 in September translates into these instructions:
Adopt every vital precaution, unprotected skin and eyes may burn rapidly. During the period from 10 a.m. to 4 p.m., UV radiation is highest. Try to avoid direct sunlight during these hours. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades. Even when the sky is cloudy, apply generously and frequently reapply a sunscreen with SPF 30 or more, especially post every swim or outdoor exercise. Attention! The reflection of both water and sand can increase the intensity of UV rays.