September weather forecast
Cozumel, Mexico

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.

Temperature

Cozumel's September average high-temperature settles at a still hot 31.9°C, showing a near match with the preceding month. Throughout September nights, Cozumel experiences a consistent temperature average of 23.6°C.

Heat index

September's mean heat index is evaluated at a blazing hot 47°C. On guard: Heat exhaustion and heat cramps are predicted. Heatstroke is a potential hazard with continuous physical effort.
Take into consideration that the heat index values are calculated for shade and light wind conditions. The presence of direct sunlight can raise the heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'felt air temperature', gauges the sensation of temperature factoring in the air's moisture content. An individual's temperature experience can be influenced by extra factors, including metabolic differences, activity levels, and clothing. Always consider that direct sunlight exposure might heighten the heat's effects, pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely vital to babies and toddlers. Young ones often underestimate the need for rest and rehydration. Thirst appears late in dehydration - hence, it is important to keep hydrated, particularly during prolonged physical activities.
The human body cools itself through perspiration, as excessive warmth is removed from the body through sweat evaporation. Under high air temperature and humidity (high heat index) conditions, perspiration is limited, and the perception of heat is increased. Heat-related disorders may develop if heat gain in the body overshadows its cooling capacity, leading to elevated temperatures.

Humidity

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

Rainfall

In Cozumel, during September, the rain falls for 15.4 days and regularly aggregates up to 240mm of precipitation. Throughout the year, there are 119.9 rainfall days, and 1490mm of precipitation is accumulated.

Sea temperature

The months with the warmest seawater in Cozumel are July through October, with an average sea temperature of 29°C.
Note: For any water activity, having surface water temperatures from 25°C to 29°C is considered outstanding and highly delightful for lengthened periods.

Daylight

In September, the average length of the day in Cozumel is 12h and 15min.
On the first day of September in Cozumel, Mexico, sunrise is at 6:31 am and sunset at 7:03 pm. On the last day of the month, sunrise is at 6:38 am and sunset at 6:36 pm EST.

Sunshine

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

UV index

In September, the average daily maximum UV index is 11. A UV Index reading of 11, and higher, represents an extreme threat to health from exposure to the Sun's UV rays for the average person.
Note: The maximum UV index of 11 during September leads to these instructions:
Execute every important safeguard, as unprotected skin and eyes could burn within moments. Attempt to stay under shade and limit exposure to the Sun between 10 a.m. and 4 p.m., when UV radiation is at its peak. Remember, devices such as parasols or canopies might not provide complete sun protection. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation. A sunscreen boasting a minimum SPF of 30 should be generously applied and reapplied even on cloudy days, post swim or outdoor exercise. Be vigilant! The Sun's UV rays get a boost from sand and water reflections.