September weather forecast
Brentwood, MO

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Weather in September

September, the first month of the autumn in Brentwood, is still a warm month, with an average temperature fluctuating between 79.7°F (26.5°C) and 60.1°F (15.6°C).

Temperature

A subtle shift in Brentwood's weather is observed as August turns into September, with the average high temperature reducing from 85.5°F (29.7°C) to a still warm 79.7°F (26.5°C). In the month of September, Brentwood records a consistent average low-temperature of 60.1°F (15.6°C).

Humidity

In September, the average relative humidity in Brentwood is 73%.

Rainfall

In Brentwood, during September, the rain falls for 12 days and regularly aggregates up to 1.97" (50mm) of precipitation. In Brentwood, Missouri, during the entire year, the rain falls for 144.8 days and collects up to 30.59" (777mm) of precipitation.

Snowfall

In Brentwood, snow does not fall in April through October.

Daylight

In September, the average length of the day is 12h and 25min.
On the first day of the month, sunrise is at 6:31 am and sunset at 7:31 pm. On the last day of September, sunrise is at 6:57 am and sunset at 6:45 pm CDT.

Sunshine

In Brentwood, the average sunshine in September is 9.6h.

UV index

In Brentwood, the average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the average person.
Note: A maximum daily UV index of 5 during September morphs into the following directions:
Safety measures are advised. Light-skinned individuals may experience burns in under half an hour. To protect against the Sun's most potent rays, avoid direct exposure around midday. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in Brentwood in September?

The high-temperature during September is 79.7°F (26.5°C) and the low-temperature is 60.1°F (15.6°C). The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which calculates the temperature value influenced by the moisture in the air, in August is computed to be 95°F (35°C).

What is the average humidity in September in Brentwood?

In Brentwood, Missouri, the average relative humidity in September is 73%.

How many days does it rain in September in Brentwood?

In September, the rain falls for 12 days. Throughout September, 1.97" (50mm) of precipitation is accumulated.

When it does not snow in Brentwood?

In Brentwood, snow does not fall in April through October.

What is the average length of the day in September in Brentwood?

In September, the average day length in Brentwood, Missouri, is 12h and 25min.

What time are sunrise and sunset in September in Brentwood?

In September, on the first day of the month, sunrise is at 6:31 am and sunset at 7:31 pm. On the last day of the month, in Brentwood, Missouri, sunrise is at 6:57 am and sunset at 6:45 pm CDT.

How long on average sun shines in September in Brentwood?

The average sunshine duration in September in Brentwood is 9.6h.

How high is the UV index in September in Brentwood?

In Brentwood, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium hazard to health from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Brentwood, MO

Average temperature in September - Brentwood, MO
  • Average high temperature in September: 79.7°F

The warmest month (with the highest average high temperature) is July (86.9°F).
The month with the lowest average high temperature is January (37.8°F).

  • Average low temperature in September: 60.1°F

The month with the highest average low temperature is July (69.1°F).
The coldest month (with the lowest average low temperature) is January (24.3°F).

Average pressure in September
Brentwood, MO

Average pressure in September - Brentwood, MO
  • Average pressure in September: 30.02"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in September
Brentwood, MO

Average wind speed in September - Brentwood, MO
  • Average wind speed in September: 6mph

The windiest month (with the highest average wind speed) is January (9.2mph).
The calmest months (with the lowest average wind speed) are July and August (5.5mph).

Average humidity in September
Brentwood, MO

Average humidity in September - Brentwood, MO
  • Average humidity in September: 73%

The month with the highest relative humidity is May (78%).
The month with the lowest relative humidity is October (70%).

Average rainfall in September
Brentwood, MO

Average rainfall in September - Brentwood, MO
  • Average rainfall in September: 1.97"

The wettest month (with the highest rainfall) is May (3.58").
The driest month (with the least rainfall) is February (1.69").

Average rainfall days in September
Brentwood, MO

Average rainfall days in September - Brentwood, MO
  • Average rainfall days in September: 12 days

The month with the highest number of rainy days is May (16.9 days).
The month with the least rainy days is January (6.5 days).

Average snowfall in September
Brentwood, MO

Average snowfall in September - Brentwood, MO
  • Average snowfall in September: 0"

The month with the highest snowfall is February (2.6").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in September
Brentwood, MO

Average snowfall days in September - Brentwood, MO
  • Average snowfall days in September: 0.1 days

The month with the highest number of snowfall days is February (5.2 days).
The months with the least snowfall days are May, June, July and August (0 days).

Average daylight in September /
Average sunshine in September
Brentwood, MO

Average daylight in September / Average sunshine in September - Brentwood, MO
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in September: 9h and 4min

The months with the most sunshine are June and July (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).

Average sunshine days in September
Brentwood, MO

Average sunshine days in September - Brentwood, MO
  • Average sunshine days in September: 15.2 days

The month with the most sunshine days is January (21 days).
The month with the least sunshine days is June (11.2 days).

Average UV index in September
Brentwood, MO

Average UV index in September - Brentwood, MO
  • Average UV index in September: 5

The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February and December (UV index 2).

Average cloud cover in September
Brentwood, MO

Average cloud cover in September - Brentwood, MO
  • Average cloud cover in September: 28

The month with the most cloud cover is January (Cloud cover 50).
The month with the least cloud cover is August (Cloud cover 27).

Average visibility in September
Brentwood, MO

Average visibility in September - Brentwood, MO
  • 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).

Brentwood, Missouri, USA

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