Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
A moderate decline in average high-temperatures is noted in September, moving from a torrid 100°F (37.8°C) in August to a tropical 93°F (33.9°C). San Isidro records a steady low-temperature average of 77°F (25°C) during September.Heat index
The heat index value during September is evaluated at a blistering 109.4°F (43°C). Keep wary: Heat cramps along with heat exhaustion are expected. Heatstroke is a possible outcome of ongoing activity.Regarding the heat index, one should be aware it's determined by shaded settings and mild winds. Being under direct sunlight might amplify the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'feels like', is a metric representing the sensation of warmth when air temperature and moisture come together. The influence of weather can be personal, changing with an individual's body mass, height, and level of physical exertion. It is noteworthy to mention that direct sunlight exposure can augment the felt temperature, leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for children. Children frequently underestimate the importance of resting and drinking fluids. Thirst is a symptom of advanced dehydration - hence the need to hydrate regularly, especially during protracted physical exercises.
In high temperatures, perspiration kicks in, allowing the human body to cool down through the evaporation of sweat. In high relative humidity, the body's ability to evaporate heat is diminished, resulting in a heightened feeling of warmth. Should the body fail to balance its heat gain, the escalating temperature poses health challenges.
Humidity
The average relative humidity in September is 62%.Rainfall
September is the month with the most rainfall. Rain falls for 15.3 days and accumulates 2.56" (65mm) of precipitation.Snowfall
In San Isidro, snow does not fall in March through December.Daylight
In September, the average length of the day is 12h and 18min.On the first day of the month, sunrise is at 7:13 am and sunset at 7:53 pm. On the last day of September, sunrise is at 7:26 am and sunset at 7:20 pm CDT.
Sunshine
In September, the average sunshine is 8.6h.UV index
In San Isidro, Texas, the average daily maximum UV index in September is 7. A UV Index estimate of 6 to 7 represents a high health risk from unprotected exposure to Sun's UV rays for the average person.Note: The daily high UV index of 7 in September translates into this advice:
Apply measures and align with sun safety principles. Safeguarding against skin and eye injury is pivotal. The Sun emits the most powerful UV radiation between 10 a.m. and 4 p.m. Try to avoid direct sunlight during this period. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot does it get in September?
What is the average humidity in September in San Isidro?
What is the rainiest month in San Isidro?
How much does it rain in September?
When it does not snow?
What is the average length of the day in September?
What time are sunrise and sunset in September in San Isidro?
How many hours of sunshine does San Isidro have in September?
What is the UV index intensity in September?
Average temperature in September
San Isidro, TX
- Average high temperature in September: 93°F
The warmest month (with the highest average high temperature) is August (100°F).
The month with the lowest average high temperature is January (69.8°F).
- Average low temperature in September: 77°F
The month with the highest average low temperature is August (80.1°F).
The coldest month (with the lowest average low temperature) is January (52.7°F).
Average pressure in September
San Isidro, TX
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.12"Hg).
The months with the lowest atmospheric pressure are May and June (29.87"Hg).
Average wind speed in September
San Isidro, TX
- Average wind speed in September: 9.9mph
The windiest month (with the highest average wind speed) is July (13.9mph).
The calmest month (with the lowest average wind speed) is December (9.2mph).
Average humidity in September
San Isidro, TX
- Average humidity in September: 62%
The month with the highest relative humidity is December (65%).
The month with the lowest relative humidity is August (53%).
Average rainfall in September
San Isidro, TX
- Average rainfall in September: 2.56"
The wettest month (with the highest rainfall) is September (2.56").
The driest month (with the least rainfall) is February (0.47").
Average rainfall days in September
San Isidro, TX
- Average rainfall days in September: 15.3 days
The month with the highest number of rainy days is September (15.3 days).
The month with the least rainy days is February (5.8 days).
Average snowfall days in September
San Isidro, TX
- Average snowfall days in September: 0 days
The months with the highest number of snowfall days are January and February (0.1 days).
The months with the least snowfall days are March, April, May, June, July, August, September, October, November and December (0 days).
Average daylight in September /
Average sunshine in September
San Isidro, TX
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 13h and 48min).
The month with the shortest days is December (Average daylight: 10h and 30min).
- Average sunshine in September: 8h and 4min
The months with the most sunshine are June and July (Average sunshine: 11h and 18min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).
Average sunshine days in September
San Isidro, TX
- Average sunshine days in September: 12.9 days
The months with the most sunshine days are July and August (22.6 days).
The month with the least sunshine days is September (12.9 days).
Average UV index in September
San Isidro, TX
- Average UV index in September: 7
The months with the highest UV index are July and August (UV index 8).
The month with the lowest UV index is December (UV index 4).
Average cloud cover in September
San Isidro, TX
- Average cloud cover in September: 30
The month with the most cloud cover is December (Cloud cover 36).
The month with the least cloud cover is August (Cloud cover 16).
Average visibility in September
San Isidro, TX
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
San Isidro, Texas, USA
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