September weather forecast
Webster Groves, MO

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Weather in September

September marks the onset of fall in Webster Groves, bringing significant changes to the climate. The longing for cooler climes finds relief as temperatures begin to recede. Outdoor activities remain prevalent, albeit the preference shifts towards bonfires, hiking, and apple picking. Median rainfall reduces to 1.97" (50mm), making the weather less erratic compared to previous months. The changing season makes September a particularly charming and colorful time to visit the city.

Temperature

September ushers in a minute temperature change, with average high-temperatures reducing from August's moderately hot 85.5°F (29.7°C) to a still warm 79.7°F (26.5°C). Nighttime temperature experiences an average drop to a refreshing 60.1°F (15.6°C) in September.

Humidity

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

Rainfall

In September, the rain falls for 12 days. Throughout September, 1.97" (50mm) of precipitation is accumulated. In Webster Groves, Missouri, during the entire year, the rain falls for 144.8 days and collects up to 30.59" (777mm) of precipitation.

Snowfall

In Webster Groves, Missouri, snow does not fall in April through October.

Daylight

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

Sunshine

In Webster Groves, the average sunshine in September is 9.6h.

UV index

In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for the ordinary person.
Note: A daily maximum UV index of 5 in September translates into the following instructions:
Be mindful. Those with pale skin might receive burns in fewer than 30 minutes. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses. Take heed! The reflection of snow can intensify the Sun's UV radiation nearly double.
Updated: Jun 16, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures?

During September, Webster Groves experiences an average high-temperature of 79.7°F (26.5°C) and a low-temperature of 60.1°F (15.6°C). In August, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which takes the relative humidity and factors it into the air temperature reading, is calculated to be 95°F (35°C).

What is the average humidity in September?

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

How much does it rain in September?

In Webster Groves, Missouri, during September, the rain falls for 12 days and regularly aggregates up to 1.97" (50mm) of precipitation.

When it does not snow?

April through October are months without snowfall.

How many hours of daylight does Webster Groves have in September?

The average day length in September is 12h and 25min.

When is the sunrise / sunset in September?

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, sunrise is at 6:57 am and sunset at 6:45 pm CDT.

How long on average sun shines in September?

In Webster Groves, the average sunshine duration in September is 9.6h.

What is the UV index reading in September?

In September, the average daily maximum UV index is 5. A UV Index of 3 to 5 symbolizes a moderate health threat from unprotected exposure to 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
Webster Groves, MO

Average temperature in September - Webster Groves, 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
Webster Groves, MO

Average pressure in September - Webster Groves, 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
Webster Groves, MO

Average wind speed in September - Webster Groves, 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
Webster Groves, MO

Average humidity in September - Webster Groves, 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
Webster Groves, MO

Average rainfall in September - Webster Groves, 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
Webster Groves, MO

Average rainfall days in September - Webster Groves, 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
Webster Groves, MO

Average snowfall in September - Webster Groves, 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
Webster Groves, MO

Average snowfall days in September - Webster Groves, 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
Webster Groves, MO

Average daylight in September / Average sunshine in September - Webster Groves, 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
Webster Groves, MO

Average sunshine days in September - Webster Groves, 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
Webster Groves, MO

Average UV index in September - Webster Groves, 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
Webster Groves, MO

Average cloud cover in September - Webster Groves, 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
Webster Groves, MO

Average visibility in September - Webster Groves, 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).

Webster Groves, Missouri, USA

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