September weather forecast and climate
Piedras Negras, Mexico

The first month of the autumn, September, is also a hot month in Piedras Negras, Mexico, with average temperature fluctuating between 23.6°C (74.5°F) and 32.6°C (90.7°F).

Temperature

In Piedras Negras, the average high-temperature in September slightly decreases, from a torrid 37.2°C (99°F) in August, to a tropical 32.6°C (90.7°F). The average low-temperature, in September, is 23.6°C (74.5°F).

Heat index

In September, the average heat index is estimated at a sweltering 37.9°C (100.2°F). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
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', 'apparent temperature', or 'feels like', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. This effect is individual, with diverse people perceiving weather differently for numerous reasons (differences in body mass, height, and shape, metabolic differences, pregnancy), 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.
To prevent overheating and help regulate its internal temperature, the human body sweat and rely on the evaporation to cool down. When the relative humidity is high, the evaporation rate is reduced. The warmth is removed from the body at a lower rate, causing the body to retain more heat than it would in dry air. If the body can not disperse the excessive heat and body temperature reaches conditions of hyperthermia, above 37.5°C (99.5°F) to 38.3°C (100.9°F), thermal conditions are potentially life-threatening.

Humidity

In September, the average relative humidity is 58%.

Rainfall

In Piedras Negras, it is raining for 13.8 days, with typically 55mm (2.17") of accumulated precipitation. Throughout the year, in Piedras Negras, there are 89.7 rainfall days, and 341mm (13.43") of precipitation is accumulated.

Snowfall

In Piedras Negras snow does not fall in January through November.

Daylight

In Piedras Negras, the average length of the day in September is 12.3h.

Sunshine

In September, the average sunshine in Piedras Negras is 8.6h.

UV index

In Piedras Negras, the average daily maximum UV index is 6. A UV Index estimate of 6 to 7 represents a high health hazard from unprotected exposure to the Sun's UV rays for average individuals.
Note: The average daily UV index of 6 in September transform into the following instructions:
Take precautions and utilize sun safety practices. Protection against the skin and eye damage is required. 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. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.

What is the temperature in September in Piedras Negras?

In Piedras Negras, Mexico, in September, the average high-temperature is 32.6°C (90.7°F), and the average low-temperature is 23.6°C (74.5°F). The average heat index (a.k.a. 'feels like', 'apparent temperature'), that combines both air temperature and relative humidity, in September is estimated at 37.9°C (100.2°F).

What is the average humidity in September in Piedras Negras?

The average relative humidity in September in Piedras Negras, Mexico, is 58%.

How many days does it rain in September in Piedras Negras?

In Piedras Negras, Mexico, in September, it is raining for 13.8 days, with typically 55mm (2.17") of accumulated precipitation.

When it does not snow in Piedras Negras?

In Piedras Negras snow does not fall in January through November.

How many hours of daylight does Piedras Negras have in September?

In September, the average length of the day in Piedras Negras is 12.3h.

How many hours of sunshine does Piedras Negras have in September?

The average sunshine in September is 8.6h.

What is the UV index reading in September in Piedras Negras?

The average daily maximum UV index in September in Piedras Negras, Mexico, is 6. A UV Index of 6 to 7 symbolizes a high health vulnerability from the exposure to the Sun's UV radiation.
Average temperature in September - Piedras Negras, Mexico
  • Average high temperature in September: 32.6°C

The warmest month (with the highest average high temperature) is August (37.2°C).
The month with the lowest average high temperature is January (18.3°C).

  • Average low temperature in September: 23.6°C

The month with the highest average low temperature is August (26.3°C).
The coldest month (with the lowest average low temperature) is January (8.3°C).

Average pressure in September - Piedras Negras, Mexico
  • Average pressure in September: 1014.1mbar

The month with the highest atmospheric pressure is January (1020.7mbar).
The month with the lowest atmospheric pressure is May (1011.6mbar).

Average wind speed in September - Piedras Negras, Mexico
  • Average wind speed in September: 14.5km/h

The windiest month (with the highest average wind speed) is June (18.8km/h).
The calmest month (with the lowest average wind speed) is December (12.4km/h).

Average humidity in September - Piedras Negras, Mexico
  • Average humidity in September: 58%

The month with the highest relative humidity is November (60%).
The month with the lowest relative humidity is August (47%).

Average rainfall in September - Piedras Negras, Mexico
  • Average rainfall in September: 55mm

The wettest month (with the highest rainfall) is May (75mm).
The driest months (with the least rainfall) are January and February (8mm).

Average rainfall days in September - Piedras Negras, Mexico
  • Average rainfall days in September: 13.8 days

The month with the highest number of rainy days is September (13.8 days).
The month with the least rainy days is January (4.3 days).

Average snowfall in September - Piedras Negras, Mexico
  • Average snowfall in September: 0mm

The month with the highest snowfall is December (1mm).
Months with the least snowfall are January, February, March, April, May, June, July, August, September, October and November (0mm).

Average snowfall days in September - Piedras Negras, Mexico
  • Average snowfall days in September: 0 days

Months with the highest number of snowfall days are January, February and December (0.1 days).
Months with the least snowfall days are March, April, May, June, July, August, September, October and November (0 days).

Average daylight in September / Average sunshine in September - Piedras Negras, Mexico
  • Average daylight in September: 12.3h

The month with the longest days is June (Average daylight: 14h).
The month with the shortest days is December (Average daylight: 10.3h).

  • Average sunshine in September: 8.6h

The month with the most sunshine is June (Average sunshine: 11.1h).
The month with the least sunshine is November (Average sunshine: 6h).

Average sunshine days in September - Piedras Negras, Mexico
  • Average sunshine days in September: 14.7 days

The month with the most sunshine days is January (25.6 days).
The month with the least sunshine days is September (14.7 days).

Average UV index in September - Piedras Negras, Mexico
  • Average UV index in September: 6

Months with the highest UV index are June, July and August (UV index 8).
Months with the lowest UV index are January and December (UV index 4).

Average cloud cover in September - Piedras Negras, Mexico
  • Average cloud cover in September: 29

The month with the most cloud cover is May (Cloud cover 32).
The month with the least cloud cover is August (Cloud cover 16).

Average visibility in September - Piedras Negras, Mexico
  • Average visibility in September: 10km

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).