September weather forecast
Mehlville, MO

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Weather in September

September marks the onset of autumn in Mehlville, bringing a welcome relief from the summer heat. A significant feature of September is the rapid reduction in daylight hours, as days grow noticeably shorter. The decline in temperature progresses but doesn't drastically affect the overall warmth. As an intriguing observation, rainfall is significantly low, with an average of 2.13" (54mm) across the entire month. The calm winds and mid-level humidity further enhance the appeal of the weather.

Temperature

The beginning of September in Mehlville brings a minor change in the average high-temperature, shifting from 85.6°F (29.8°C) in August to a still moderately hot 79.7°F (26.5°C). Throughout September, Mehlville's nights cool down to an average of 59.9°F (15.5°C).

Humidity

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

Rainfall

In Mehlville, in September, it is raining for 12.6 days, with typically 2.13" (54mm) of accumulated precipitation. In Mehlville, during the entire year, the rain falls for 146.1 days and collects up to 32.36" (822mm) of precipitation.

Snowfall

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

Daylight

The average length of the day in September in Mehlville is 12h and 25min.
On the first day of the month, sunrise is at 6:31 am and sunset at 7:30 pm. On the last day of September, in Mehlville, sunrise is at 6:56 am and sunset at 6:45 pm CDT.

Sunshine

In Mehlville, the average sunshine in September is 9.4h.

UV index

The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for the average person.
Note: The maximum UV index, 5 during September, leads to the following recommendations:
Undertake protective steps - Obligation to safeguard skin and eyes from harm is in place. When the Sun is at its strongest around midday, find shade and limit exposure. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage.
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Frequently asked questions

What are September temperatures in Mehlville?

An average high-temperature, in September, in Mehlville, is 79.7°F (26.5°C) and the average low-temperature is 59.9°F (15.5°C). In August, the average heat index (a.k.a. 'apparent temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, is calculated to be 96.8°F (36°C).

What is the average humidity in September in Mehlville?

The average relative humidity in September in Mehlville is 73%.

How many days does it rain in September in Mehlville?

In Mehlville, in September, it is raining for 12.6 days, with typically 2.13" (54mm) of accumulated precipitation.

When it does not snow in Mehlville?

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

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

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

What time are sunrise and sunset in September in Mehlville?

On the first day of September in Mehlville, Missouri, sunrise is at 6:31 am and sunset at 7:30 pm. On the last day of the month, sunrise is at 6:56 am and sunset at 6:45 pm CDT.

How long on average sun shines in September in Mehlville?

In Mehlville, Missouri, the average sunshine duration in September is 9.4h.

How high is the UV index in September in Mehlville?

In Mehlville, Missouri, the average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium health risk from exposure to Sun's UV rays.
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
Mehlville, MO

Average temperature in September - Mehlville, 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 (37.9°F).

  • Average low temperature in September: 59.9°F

The month with the highest average low temperature is July (69.3°F).
The coldest month (with the lowest average low temperature) is January (25°F).

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Average pressure in September
Mehlville, MO

Average pressure in September - Mehlville, 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).

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Average wind speed in September
Mehlville, MO

Average wind speed in September - Mehlville, MO
  • Average wind speed in September: 5.9mph

The windiest month (with the highest average wind speed) is January (9.1mph).
The calmest months (with the lowest average wind speed) are July and August (5.5mph).

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Average humidity in September
Mehlville, MO

Average humidity in September - Mehlville, 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 (71%).

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Average rainfall in September
Mehlville, MO

Average rainfall in September - Mehlville, MO
  • Average rainfall in September: 2.13"

The wettest month (with the highest rainfall) is May (3.94").
The driest months (with the least rainfall) are February and November (1.77").

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Average rainfall days in September
Mehlville, MO

Average rainfall days in September - Mehlville, MO
  • Average rainfall days in September: 12.6 days

The month with the highest number of rainy days is July (16.9 days).
The months with the least rainy days are January and February (6.8 days).

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Average snowfall in September
Mehlville, MO

Average snowfall in September - Mehlville, 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").

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Average snowfall days in September
Mehlville, MO

Average snowfall days in September - Mehlville, MO
  • Average snowfall days in September: 0 days

The months with the highest number of snowfall days are January and February (4.8 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

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

Average daylight in September / Average sunshine in September - Mehlville, 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 2min

The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).

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Average sunshine days in September
Mehlville, MO

Average sunshine days in September - Mehlville, MO
  • Average sunshine days in September: 15.5 days

The month with the most sunshine days is January (20.9 days).
The month with the least sunshine days is June (11.6 days).

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Average UV index in September
Mehlville, MO

Average UV index in September - Mehlville, 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).

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Average cloud cover in September
Mehlville, MO

Average cloud cover in September - Mehlville, MO
  • Average cloud cover in September: 30

The month with the most cloud cover is January (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 28).

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Average visibility in September
Mehlville, MO

Average visibility in September - Mehlville, 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).

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Mehlville, Missouri, USA

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