September weather forecast
Merida, Mexico

The Santa Ana Church in Merida, Mexico, surrounded by beautiful flowers and palm trees
The Santa Ana Church in Merida, Mexico, surrounded by beautiful flowers and palm trees

September

Weather in September

With the commencement of September, the weather takes another turn in Merida. The city receives the highest amount of rainfall, up to 70mm (2.76") on average, as compared to other months. Even though the rainfall is significant, temperatures remain quite high. The overall weather can be described as rainy and humid, making it ideal for indoor activities. Since outdoor activities may get hindered due to significant rainfall, flexible plans are advised.

Temperature

Merida's average high-temperature in September sits at a hot 33.6°C (92.5°F), showing little difference from the previous month. Throughout September, Merida experiences a low-temperature average of 23.3°C (73.9°F).

Heat index

During September, the heat index is estimated at a life-threatening hot 49°C (120.2°F). Careful: Heat exhaustion and heat cramps are anticipated. With ongoing exertion, heatstroke becomes a possibility.
Be advised, the heat index considers values for conditions in shade and with a light breeze. A rise in the heat index by 15 Fahrenheit (8 Celsius) degrees may result from direct sunlight exposure.
Note: The heat index, also known as 'feels like' or 'felt air temperature', shows a temperature sensation when both heat and moisture conditions are combined. An individual's perception of weather can be influenced by a variety of factors including metabolic differences, being pregnant, and their degree of physical exertion. One should be aware that direct sunshine can amplify the perceived temperature, raising the heat index by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are largely significant for babies and toddlers. Children often miss understanding the importance of rest and rehydration. Thirst usually appears late during dehydration - therefore, maintaining hydration, particularly during long physical activities, is essential.
The physiological way the human body responds to excessive heat is by inducing perspiration, using sweat evaporation as a cooling mechanism. During high air temperature and humidity (high heat index), the process of perspiration is hindered, intensifying the sensation of heat. As the body accumulates more heat than it can release, body temperature goes up, increasing the risk of heat-related health issues.

Humidity

September and October, with an average relative humidity of 78%, are the most humid months.

Rainfall

In Merida, in September, it is raining for 20.4 days, with typically 70mm (2.76") of accumulated precipitation. Throughout the year, there are 167.3 rainfall days, and 536mm (21.1") of precipitation is accumulated.

Daylight

In September, the average length of the day is 12h and 16min.
On the first day of September, sunrise is at 5:42 am and sunset at 6:13 pm. On the last day of the month, sunrise is at 5:49 am and sunset at 5:46 pm CST.

Sunshine

In September, the average sunshine is 9.4h.

UV index

February through October, with an average maximum UV index of 7, are months with the highest UV index. A UV Index reading of 6 to 7 represents a high health risk from unprotected exposure to Sun's UV rays for average individuals.
Note: In September, the average maximum UV index of 7 translates into the following recommendations:
Enforce precautions and stick to sun safety measures. Preservation from skin and eye damage is essential. Try to minimize direct Sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Also note that objects like parasols or canopies might not provide complete sun protection. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.

Frequently asked questions

How hot does it get in September?
The high-temperature in Merida during September is 33.6°C (92.5°F) and the low-temperature is 23.3°C (73.9°F). The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which calculates the temperature value influenced by the moisture in the air, in September is estimated at 49°C (120.2°F).
What are the most humid months?
The months with the highest humidity are September and October, with an average relative humidity of 78%.
What is the average humidity in September?
The average relative humidity in September is 78%.
How many days does it rain in September?
In Merida, during September, the rain falls for 20.4 days and regularly aggregates up to 70mm (2.76") of precipitation.
What is the average length of the day in September?
In September, the average day length is 12h and 16min.
When are sunrise and sunset in September?
On the first day of September, sunrise is at 5:42 am and sunset at 6:13 pm. On the last day of the month, sunrise is at 5:49 am and sunset at 5:46 pm CST.
How long on average sun shines in September?
In Merida, the average sunshine duration in September is 9.4h.
What are the months with the highest UV index?
February through October, with an average maximum UV index of 7, are months with the highest UV index.
How high is the UV index in September?
The average daily maximum UV index in September is 7. A UV Index estimate of 6 to 7 represents a high health vulnerability from exposure to Sun's UV rays.
Average high temperature
Average low temperature
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility
Average temperature in September - Merida, Mexico
Average temperature in September
Merida, Mexico
  • Average high temperature in September: 33.6°C

The warmest month (with the highest average high temperature) is May (35.4°C).
The month with the lowest average high temperature is January (28.1°C).

  • Average low temperature in September: 23.3°C

The month with the highest average low temperature is June (24.3°C).
The coldest month (with the lowest average low temperature) is January (18.6°C).

Average pressure in September - Merida, Mexico
Average pressure in September
Merida, Mexico
  • Average pressure in September: 1011.9mbar

The month with the highest atmospheric pressure is January (1017.6mbar).
The month with the lowest atmospheric pressure is September (1011.9mbar).

Average wind speed in September - Merida, Mexico
Average wind speed in September
Merida, Mexico
  • Average wind speed in September: 10.6km/h

The windiest month (with the highest average wind speed) is March (16.1km/h).
The calmest month (with the lowest average wind speed) is September (10.6km/h).

Average humidity in September - Merida, Mexico
Average humidity in September
Merida, Mexico
  • Average humidity in September: 78%

The months with the highest relative humidity are September and October (78%).
The months with the lowest relative humidity are April and May (63%).

Average rainfall in September - Merida, Mexico
Average rainfall in September
Merida, Mexico
  • Average rainfall in September: 70mm

The wettest month (with the highest rainfall) is June (99mm).
The driest months (with the least rainfall) are February and March (12mm).

Average rainfall days in September - Merida, Mexico
Average rainfall days in September
Merida, Mexico
  • Average rainfall days in September: 20.4 days

The month with the highest number of rainy days is September (20.4 days).
The months with the least rainy days are February and March (7.2 days).

Average daylight in September / Average sunshine in September - Merida, Mexico
Average daylight in September /
Average sunshine in September
Merida, Mexico
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 13h and 24min).
The month with the shortest days is December (Average daylight: 10h and 54min).

  • Average sunshine in September: 9h and 2min

The month with the most sunshine is May (Average sunshine: 11h and 6min).
The month with the least sunshine is January (Average sunshine: 5h and 54min).

Average sunshine days in September - Merida, Mexico
Average sunshine days in September
Merida, Mexico
  • Average sunshine days in September: 8.8 days

The month with the most sunshine days is March (21.8 days).
The month with the least sunshine days is October (8.5 days).

Average UV index in September - Merida, Mexico
Average UV index in September
Merida, Mexico
  • Average UV index in September: 7

The months with the highest UV index are February, March, April, May, June, July, August, September and October (UV index 7).
The months with the lowest UV index are January, November and December (UV index 6).

Average cloud cover in September - Merida, Mexico
Average cloud cover in September
Merida, Mexico
  • Average cloud cover in September: 34

The month with the most cloud cover is January (Cloud cover 36).
The months with the least cloud cover are March and April (Cloud cover 25).

Average visibility in September - Merida, Mexico
Average visibility in September
Merida, Mexico
  • Average visibility in September: 8km

The months with the highest visibility are February, March, April, May and June (10km).
The month with the lowest visibility is September (8km).

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