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
The beginning of September brings a slight decrease in the average high-temperature, transitioning from a hot 86.2°F (30.1°C) in August to a moderately hot 79.7°F (26.5°C). The average nighttime temperature lowers to a moderate 59.9°F (15.5°C) throughout September.Humidity
In Herculaneum, the average relative humidity in September is 74%.Rainfall
In Herculaneum, Missouri, in September, it is raining for 13 days, with typically 2.13" (54mm) of accumulated precipitation. Throughout the year, there are 155 rainfall days, and 34.92" (887mm) of precipitation is accumulated.Snowfall
In Herculaneum, Missouri, snow does not fall in April through October.Daylight
In Herculaneum, the average length of the day in September 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, sunrise is at 6:57 am and sunset at 6:45 pm CDT.
Sunshine
In September, the average sunshine is 9.5h.UV index
The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for the average person.Note: The maximum UV index, 5 during September, leads to the following recommendations:
Put precautions into practice - Protective measures against sun-induced damage are advised. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow in Herculaneum?
What is the average length of the day in September?
When are sunrise and sunset in September?
How many hours of sunshine does Herculaneum have in September?
How high is the UV index in September?
Average temperature in September
Herculaneum, MO
- Average high temperature in September: 79.7°F
The warmest month (with the highest average high temperature) is July (88°F).
The month with the lowest average high temperature is January (39°F).
- Average low temperature in September: 59.9°F
The month with the highest average low temperature is July (68.2°F).
The coldest month (with the lowest average low temperature) is January (25.2°F).
Average pressure in September
Herculaneum, 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
Herculaneum, MO
- Average wind speed in September: 5.6mph
The windiest month (with the highest average wind speed) is January (9mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).
Average humidity in September
Herculaneum, MO
- Average humidity in September: 74%
The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Herculaneum, MO
- Average rainfall in September: 2.13"
The wettest month (with the highest rainfall) is May (4.25").
The driest month (with the least rainfall) is February (1.97").
Average rainfall days in September
Herculaneum, MO
- Average rainfall days in September: 13 days
The month with the highest number of rainy days is July (17.8 days).
The month with the least rainy days is January (8.2 days).
Average snowfall in September
Herculaneum, MO
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.36").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Herculaneum, MO
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (6.8 days).
The months with the least snowfall days are April, May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Herculaneum, 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 36min).
- Average sunshine in September: 9h and 3min
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 48min).
Average sunshine days in September
Herculaneum, MO
- Average sunshine days in September: 14.6 days
The month with the most sunshine days is December (19.2 days).
The month with the least sunshine days is July (10.7 days).
Average UV index in September
Herculaneum, 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, November and December (UV index 2).
Average cloud cover in September
Herculaneum, MO
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 49).
The months with the least cloud cover are June, July and August (Cloud cover 28).
Average visibility in September
Herculaneum, 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).
Herculaneum, Missouri, USA
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