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
September's arrival subtly correlates with a reduction in the average high-temperature, down from a sweltering 95.5°F (35.3°C) in August to a tropical 87.6°F (30.9°C). Throughout the month of September, the average temperature dips to a pleasant 69.6°F (20.9°C) at night.Heat index
The heat index value during September is estimated at a sweltering 96.8°F (36°C). More protective measures are required - heat exhaustion and heat cramps are likely. Heatstroke may follow lengthy activity.Metrics for the heat index primarily focus on shaded spots and light wind conditions. When under direct sunshine, the heat index may be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', shows a temperature sensation when both heat and moisture conditions are combined. One's perception of weather can be shaped by other factors, involving metabolic differences, pregnancy, and physical exertion. Awareness is key; direct sunlight can enhance the weather's impact, possibly boosting the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular importance for children. Children often overlook the need for breaks and fluid intake. Thirst is a late-stage sign of dehydration - hence, it is necessary to stay hydrated, especially during extended periods of physical activities.
To achieve cooling, the human body employs perspiration, relying on the subsequent evaporation of sweat. An elevated level of relative humidity hinders evaporation, leading to decreased heat elimination from the body, inducing a sensation of excess heat. Overheating risks increase with rising body temperatures, especially if heat release isn't efficient.
Humidity
In September, the average relative humidity in Sunnyvale is 64%.Rainfall
In Sunnyvale, during September, the rain falls for 15.3 days and regularly aggregates up to 2.8" (71mm) of precipitation. Throughout the year, there are 149.6 rainfall days, and 33.35" (847mm) of precipitation is accumulated.Snowfall
March through December are months without snowfall in Sunnyvale, Texas.Daylight
In Sunnyvale, Texas, the average length of the day in September is 12h and 22min.On the first day of the month, sunrise is at 7:01 am and sunset at 7:50 pm. On the last day of September, sunrise is at 7:20 am and sunset at 7:11 pm CDT.
Sunshine
The average sunshine in September in Sunnyvale is 8.6h.UV index
In September, the average daily maximum UV index in Sunnyvale is 6. A UV Index estimate of 6 to 7 represents a high health vulnerability from unsafe exposure to UV radiation for average individuals.Note: In September, a regular UV index of 6 translates into these guidelines:
Apply measures and align with sun safety principles. Safeguarding against skin and eye injury is pivotal. Between 10 a.m. and 4 p.m., the Sun's UV radiation is at its peak. Limit your exposure to direct sunlight during these hours. Protect your eyes, ears, face, and neck from the Sun by wearing a wide-brimmed hat.
Frequently asked questions
How hot is September in Sunnyvale?
What is the average humidity in September in Sunnyvale?
How many days does it rain in September in Sunnyvale?
When it does not snow in Sunnyvale?
How many hours of daylight does Sunnyvale have in September?
When is the sunrise / sunset in September in Sunnyvale?
How many hours of sunshine does Sunnyvale have in September?
What is the UV index intensity in September in Sunnyvale?
Average temperature in September
Sunnyvale, TX
- Average high temperature in September: 87.6°F
The warmest month (with the highest average high temperature) is August (95.5°F).
The month with the lowest average high temperature is January (54.3°F).
- Average low temperature in September: 69.6°F
The months with the highest average low temperature are July and August (75.7°F).
The coldest month (with the lowest average low temperature) is January (38.8°F).
Average pressure in September
Sunnyvale, TX
- Average pressure in September: 29.97"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Sunnyvale, TX
- Average wind speed in September: 6.6mph
The windiest month (with the highest average wind speed) is March (9.8mph).
The calmest month (with the lowest average wind speed) is September (6.6mph).
Average humidity in September
Sunnyvale, TX
- Average humidity in September: 64%
The month with the highest relative humidity is May (75%).
The month with the lowest relative humidity is August (58%).
Average rainfall in September
Sunnyvale, TX
- Average rainfall in September: 2.8"
The wettest month (with the highest rainfall) is October (4.29").
The driest month (with the least rainfall) is February (1.85").
Average rainfall days in September
Sunnyvale, TX
- Average rainfall days in September: 15.3 days
The month with the highest number of rainy days is May (15.4 days).
The month with the least rainy days is January (7.6 days).
Average snowfall in September
Sunnyvale, TX
- Average snowfall in September: 0"
The month with the highest snowfall is February (0.67").
The months with the least snowfall are March, April, May, June, July, August, September, October, November and December (0").
Average snowfall days in September
Sunnyvale, TX
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (1.2 days).
The months with the least snowfall days are April, May, June, July, August, September, October and November (0 days).
Average daylight in September /
Average sunshine in September
Sunnyvale, TX
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).
- Average sunshine in September: 8h and 4min
The month with the most sunshine is August (Average sunshine: 11h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 30min).
Average sunshine days in September
Sunnyvale, TX
- Average sunshine days in September: 13 days
The month with the most sunshine days is January (21.8 days).
The month with the least sunshine days is September (13 days).
Average UV index in September
Sunnyvale, TX
- Average UV index in September: 6
The months with the highest UV index are June, July and August (UV index 7).
The months with the lowest UV index are January and December (UV index 3).
Average cloud cover in September
Sunnyvale, TX
- Average cloud cover in September: 28
The month with the most cloud cover is February (Cloud cover 42).
The month with the least cloud cover is August (Cloud cover 20).
Average visibility in September
Sunnyvale, 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).
Sunnyvale, Texas, USA
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