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 advent notes a subtle adjustment in average high-temperature to a moderately hot 84.9°F (29.4°C) from August. An average low-temperature of 65.3°F (18.5°C) is recorded during the nights in September in Mountain Brook.Heat index
For September, the heat index is appraised at a tropical 93.2°F (34°C). Incorporate extra safety measures to avoid heat exhaustion and heat cramps. Continuous activity could provoke heatstroke.Heat index guidelines indicate values are for light wind scenarios and shaded regions. Heat index values may surge by up to 15 Fahrenheit (8 Celsius) degrees in the presence of direct sunlight.
Note: The heat index, also known as 'feels like' or 'apparent temperature', is a composite of temperature and humidity figures to convey how warm it feels. This impact is subjective, influenced by the person's physical activity and individual heat perception, affected by factors including wind, attire, and metabolic differences. By being directly under the sun, it's possible for the felt temperature to increase by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. Youngsters generally face more threats than adults given their lesser ability to sweat. Coupled with their larger skin surface relative to their small bodies and higher heat production due to their activities, they are more endangered.
Humidity
The average relative humidity in September is 72%.Rainfall
In Mountain Brook, during September, the rain falls for 12.1 days and regularly aggregates up to 1.1" (28mm) of precipitation. In Mountain Brook, during the entire year, the rain falls for 143.1 days and collects up to 18.58" (472mm) of precipitation.Snowfall
In Mountain Brook, snow does not fall in April through October.Daylight
In September, the average length of the day is 12h and 22min.On the first day of September, sunrise is at 6:21 am and sunset at 7:11 pm. On the last day of the month, sunrise is at 6:41 am and sunset at 6:32 pm CDT.
Sunshine
In Mountain Brook, the average sunshine in September is 8.8h.UV index
In Mountain Brook, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the ordinary person.Note: A typical high UV index of 5 in September suggests the following recommendations:
Be cautious. Those with fair skin can be subjected to burns in fewer than 30 minutes. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is it hot during September?
What is the average humidity in September?
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?
How many hours of sunshine does Mountain Brook have in September?
What is the UV index reading in September in Mountain Brook?
Average temperature in September
Mountain Brook, AL
- Average high temperature in September: 84.9°F
The warmest month (with the highest average high temperature) is July (91°F).
The month with the lowest average high temperature is January (50.7°F).
- Average low temperature in September: 65.3°F
The month with the highest average low temperature is July (71.1°F).
The coldest month (with the lowest average low temperature) is January (35.2°F).
Average pressure in September
Mountain Brook, AL
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.98"Hg).
Average wind speed in September
Mountain Brook, AL
- Average wind speed in September: 4.8mph
The windiest month (with the highest average wind speed) is February (7.4mph).
The calmest months (with the lowest average wind speed) are July and August (4.5mph).
Average humidity in September
Mountain Brook, AL
- Average humidity in September: 72%
The month with the highest relative humidity is December (79%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Mountain Brook, AL
- Average rainfall in September: 1.1"
The wettest month (with the highest rainfall) is June (1.97").
The driest month (with the least rainfall) is November (1.02").
Average rainfall days in September
Mountain Brook, AL
- Average rainfall days in September: 12.1 days
The month with the highest number of rainy days is July (17.6 days).
The month with the least rainy days is November (7.9 days).
Average snowfall in September
Mountain Brook, AL
- Average snowfall in September: 0"
The month with the highest snowfall is January (0.12").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Mountain Brook, AL
- Average snowfall days in September: 0 days
The months with the highest number of snowfall days are January and February (0.8 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Mountain Brook, AL
- 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 5min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).
Average sunshine days in September
Mountain Brook, AL
- Average sunshine days in September: 15.7 days
The month with the most sunshine days is October (20.9 days).
The month with the least sunshine days is July (11.1 days).
Average UV index in September
Mountain Brook, AL
- Average UV index in September: 5
The months with the highest UV index are July and August (UV index 7).
The month with the lowest UV index is December (UV index 2).
Average cloud cover in September
Mountain Brook, AL
- Average cloud cover in September: 30
The month with the most cloud cover is February (Cloud cover 48).
The months with the least cloud cover are June and September (Cloud cover 30).
Average visibility in September
Mountain Brook, AL
- 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).
Mountain Brook, Alabama, USA
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