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 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 minor decrease in the average high-temperature is observed during September, shifting from a very hot 98.2°F (36.8°C) in August to a tropical 92.5°F (33.6°C). Throughout September, San Juan's nights cool down to an average of 77.2°F (25.1°C).Heat index
Throughout September, the heat index is appraised at a blistering 109.4°F (43°C). Watchful: Heat cramps and heat exhaustion are predicted. Continued exertion could lead to heatstroke.The heat index's values are generally associated with conditions in shade and light breezes. The heat index has the potential to rise by 15 Fahrenheit (8 Celsius) degrees with direct sunshine exposure.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', is a composite of temperature and humidity figures to convey how warm it feels. Additional elements encompassing metabolic differences, the degree of physical activity, and attire can impact the individual's perception of temperature. Exposure to direct sun rays can influence the heat you feel, pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values are essentially critical for children. Kids often lack the knowledge about the necessity to take breaks and consume liquids. Thirst, as a late symptom of dehydration, necessitates the maintenance of hydration, particularly during enduring physical activities.
Humans rely on perspiration as a cooling mechanism, wherein the evaporating sweat counteracts excessive warmth. An increase in relative humidity hinders the body's normal cooling function by reducing evaporation, thereby decreasing the rate of body cooling and enhancing the sense of warmth. Temperature imbalances caused by excessive heat retention can trigger heat-related maladies.
Humidity
In September, the average relative humidity is 65%.Rainfall
September is the month with the most rainfall. Rain falls for 15.1 days and accumulates 1.46" (37mm) of precipitation.Snowfall
In San Juan, snow does not fall in February through December.Daylight
In San Juan, Texas, the average length of the day in September is 12h and 18min.On the first day of September, sunrise is at 7:12 am and sunset at 7:51 pm. On the last day of the month, sunrise is at 7:24 am and sunset at 7:19 pm CDT.
Sunshine
In San Juan, Texas, the average sunshine in September is 8.6h.UV index
In San Juan, the average daily maximum UV index in September is 7. A UV Index estimate of 6 to 7 represents a high threat to health from unsafe exposure to UV radiation for the ordinary person.Note: During September, 7 as the daily maximum UV index converts into the following advice:
Avoid excessive sunlight. Those with lighter skin may experience burning in less than 20 minutes. The Sun's UV radiation is most potent between 10 a.m. and 4 p.m. Try to limit direct exposure to the Sun during this period. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
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?
What is the wettest month?
How many days does it rain in September?
When it does not snow?
How many hours of daylight does San Juan have in September?
What time are sunrise and sunset in September?
How many hours of sunshine does San Juan have in September?
What is the UV index intensity in September?
Average temperature in September
San Juan, TX
- Average high temperature in September: 92.5°F
The warmest month (with the highest average high temperature) is August (98.2°F).
The month with the lowest average high temperature is January (69.6°F).
- Average low temperature in September: 77.2°F
The month with the highest average low temperature is August (79.7°F).
The coldest month (with the lowest average low temperature) is January (53.4°F).
Average pressure in September
San Juan, TX
- Average pressure in September: 29.91"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 Juan, TX
- Average wind speed in September: 8.9mph
The windiest month (with the highest average wind speed) is May (12.4mph).
The calmest month (with the lowest average wind speed) is September (8.9mph).
Average humidity in September
San Juan, TX
- Average humidity in September: 65%
The month with the highest relative humidity is May (69%).
The month with the lowest relative humidity is August (59%).
Average rainfall in September
San Juan, TX
- Average rainfall in September: 1.46"
The wettest month (with the highest rainfall) is September (1.46").
The driest months (with the least rainfall) are January and February (0.31").
Average rainfall days in September
San Juan, TX
- Average rainfall days in September: 15.1 days
The month with the highest number of rainy days is September (15.1 days).
The month with the least rainy days is February (5.4 days).
Average snowfall in September
San Juan, TX
- Average snowfall in September: 0"
The month with the highest snowfall is January (0.12").
The months with the least snowfall are February, March, April, May, June, July, August, September, October, November and December (0").
Average snowfall days in September
San Juan, TX
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (0.1 days).
The months with the least snowfall days are February, March, April, May, June, July, August, September, October, November and December (0 days).
Average daylight in September /
Average sunshine in September
San Juan, 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 month with the most sunshine is July (Average sunshine: 11h and 24min).
The month with the least sunshine is December (Average sunshine: 5h and 30min).
Average sunshine days in September
San Juan, TX
- Average sunshine days in September: 12.5 days
The month with the most sunshine days is July (23 days).
The month with the least sunshine days is September (12.5 days).
Average UV index in September
San Juan, 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 Juan, TX
- Average cloud cover in September: 30
The month with the most cloud cover is December (Cloud cover 39).
The month with the least cloud cover is August (Cloud cover 18).
Average visibility in September
San Juan, 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 Juan, Texas, USA
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